31787456811381 has 12 divisors (see below), whose sum is σ = 45924125846508. Its totient is φ = 21187525357824.

The previous prime is 31787456811371. The next prime is 31787456811419. The reversal of 31787456811381 is 18311865478713.

31787456811381 is a `hidden beast` number, since 3 + 1 + 78 + 7 + 456 + 81 + 1 + 38 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10430580988881 + 21356875822500 = 3229641^2 + 4621350^2 .

It is not a de Polignac number, because 31787456811381 - 2¹⁵ = 31787456778613 is a prime.

It is a super-2 number, since 2×31787456811381² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31787456811361) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 342660750 + ... + 342753503.

It is an arithmetic number, because the mean of its divisors is an integer number (3827010487209).

Almost surely, 2^{31787456811381} is an apocalyptic number.

It is an amenable number.

31787456811381 is a deficient number, since it is larger than the sum of its proper divisors (14136669035127).

31787456811381 is a wasteful number, since it uses less digits than its factorization.

31787456811381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685419412 (or 685419409 counting only the distinct ones).

The product of its digits is 27095040, while the sum is 63.

The spelling of 31787456811381 in words is "thirty-one trillion, seven hundred eighty-seven billion, four hundred fifty-six million, eight hundred eleven thousand, three hundred eighty-one".