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231020031 = 31119368453
BaseRepresentation
bin11011100010100…
…01010111111111
3121002201000220110
431301101113333
5433120120111
634531321103
75503431534
oct1561212777
9532630813
10231020031
1110944a850
1265450193
1338b28658
1422978d8b
15154355a6
hexdc515ff

231020031 has 16 divisors (see below), whose sum is σ = 353715840. Its totient is φ = 132642720.

The previous prime is 231019991. The next prime is 231020047. The reversal of 231020031 is 130020132.

It is a happy number.

It is not a de Polignac number, because 231020031 - 219 = 230495743 is a prime.

It is a super-2 number, since 2×2310200312 = 106740509446481922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 231019989 and 231020016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231020051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 183600 + ... + 184853.

It is an arithmetic number, because the mean of its divisors is an integer number (22107240).

Almost surely, 2231020031 is an apocalyptic number.

231020031 is a deficient number, since it is larger than the sum of its proper divisors (122695809).

231020031 is a wasteful number, since it uses less digits than its factorization.

231020031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368486.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 231020031 is about 15199.3431108058. The cubic root of 231020031 is about 613.5969788155.

Adding to 231020031 its reverse (130020132), we get a palindrome (361040163).

The spelling of 231020031 in words is "two hundred thirty-one million, twenty thousand, thirty-one".

Divisors: 1 3 11 19 33 57 209 627 368453 1105359 4052983 7000607 12158949 21001821 77006677 231020031