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190191681 = 3245972
BaseRepresentation
bin10110101011000…
…01100001000001
3111020212201221100
423111201201001
5342142113211
630512245013
74466413461
oct1325414101
9436781840
10190191681
11983a3909
1253840769
1330531a74
141b38bba1
1511a6d156
hexb561841

190191681 has 9 divisors (see below), whose sum is σ = 274781091. Its totient is φ = 126766872.

The previous prime is 190191649. The next prime is 190191689. The reversal of 190191681 is 186191091.

The square root of 190191681 is 13791.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 13727025 + 176464656 = 3705^2 + 13284^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 190191681 - 25 = 190191649 is a prime.

It is a super-2 number, since 2×1901916812 = 72345751043211522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (190191689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 39075 + ... + 43671.

Almost surely, 2190191681 is an apocalyptic number.

190191681 is the 13791-st square number.

190191681 is the 6896-th centered octagonal number.

It is an amenable number.

190191681 is a deficient number, since it is larger than the sum of its proper divisors (84589410).

190191681 is an frugal number, since it uses more digits than its factorization.

190191681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9200 (or 4600 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 36.

The cubic root of 190191681 is about 575.0829682420.

Multiplying 190191681 by its sum of digits (36), we get a square (6846900516 = 827462).

The spelling of 190191681 in words is "one hundred ninety million, one hundred ninety-one thousand, six hundred eighty-one".

Divisors: 1 3 9 4597 13791 41373 21132409 63397227 190191681