31181490365257 has 4 divisors (see below), whose sum is σ = 31339772042436. Its totient is φ = 31023208688080.

The previous prime is 31181490365203. The next prime is 31181490365299. The reversal of 31181490365257 is 75256309418113.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26555274418761 + 4626215946496 = 5153181^2 + 2150864^2 .

It is a cyclic number.

It is not a de Polignac number, because 31181490365257 - 2³⁵ = 31147130626889 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31181490365198 and 31181490365207.

It is not an unprimeable number, because it can be changed into a prime (31181490365657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79140838294 + ... + 79140838687.

It is an arithmetic number, because the mean of its divisors is an integer number (7834943010609).

It is a 2-persistent number, because it is pandigital, and so is 2⋅31181490365257 = 62362980730514, but 3⋅31181490365257 = 93544471095771 is not.

Almost surely, 2^{31181490365257} is an apocalyptic number.

It is an amenable number.

31181490365257 is a deficient number, since it is larger than the sum of its proper divisors (158281677179).

31181490365257 is a wasteful number, since it uses less digits than its factorization.

31181490365257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158281677178.

The product of its (nonzero) digits is 5443200, while the sum is 55.

The spelling of 31181490365257 in words is "thirty-one trillion, one hundred eighty-one billion, four hundred ninety million, three hundred sixty-five thousand, two hundred fifty-seven".