31857874561 has 2 divisors, whose sum is σ = 31857874562. Its totient is φ = 31857874560.

The previous prime is 31857874549. The next prime is 31857874577. The reversal of 31857874561 is 16547875813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28094788225 + 3763086336 = 167615^2 + 61344^2 .

It is a cyclic number.

It is not a de Polignac number, because 31857874561 - 2¹¹ = 31857872513 is a prime.

It is not a weakly prime, because it can be changed into another prime (31857872561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15928937280 + 15928937281.

It is an arithmetic number, because the mean of its divisors is an integer number (15928937281).

Almost surely, 2^31857874561 is an apocalyptic number.

It is an amenable number.

31857874561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31857874561 is an equidigital number, since it uses as much as digits as its factorization.

31857874561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5644800, while the sum is 55.

The spelling of 31857874561 in words is "thirty-one billion, eight hundred fifty-seven million, eight hundred seventy-four thousand, five hundred sixty-one".