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18861649 = 4321012
BaseRepresentation
bin100011111110…
…0111001010001
31022111021022121
41013330321101
514312033044
61512134241
7316215142
oct107747121
938437277
1018861649
11a713044
126397381
133ba5251
14270dac9
1519c8984
hex11fce51

18861649 has 9 divisors (see below), whose sum is σ = 19503579. Its totient is φ = 18240600.

The previous prime is 18861643. The next prime is 18861673. The reversal of 18861649 is 94616881.

The square root of 18861649 is 4343.

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., 18122049 + 739600 = 4257^2 + 860^2 .

It is not a de Polignac number, because 18861649 - 29 = 18861137 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

Its product of digits (82944) is a multiple of the sum of its prime divisors (144).

It is not an unprimeable number, because it can be changed into a prime (18861643) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 186699 + ... + 186799.

Almost surely, 218861649 is an apocalyptic number.

18861649 is the 4343-rd square number.

18861649 is the 2172-nd centered octagonal number.

It is an amenable number.

18861649 is a deficient number, since it is larger than the sum of its proper divisors (641930).

18861649 is an frugal number, since it uses more digits than its factorization.

18861649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 144 counting only the distinct ones).

The product of its digits is 82944, while the sum is 43.

The cubic root of 18861649 is about 266.1909091756.

Multiplying 18861649 by its product of digits (82944), we get a square (1564460614656 = 12507842).

The spelling of 18861649 in words is "eighteen million, eight hundred sixty-one thousand, six hundred forty-nine".

Divisors: 1 43 101 1849 4343 10201 186749 438643 18861649