681531257 has 16 divisors (see below), whose sum is σ = 752716800. Its totient is φ = 611921040.

The previous prime is 681531181. The next prime is 681531281. The reversal of 681531257 is 752135186.

It is a cyclic number.

It is not a de Polignac number, because 681531257 - 2¹⁶ = 681465721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 681531257.

It is not an unprimeable number, because it can be changed into a prime (681531287) 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, 516044 + ... + 517362.

It is an arithmetic number, because the mean of its divisors is an integer number (47044800).

Almost surely, 2^681531257 is an apocalyptic number.

It is an amenable number.

681531257 is a deficient number, since it is larger than the sum of its proper divisors (71185543).

681531257 is a wasteful number, since it uses less digits than its factorization.

681531257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1876.

The product of its digits is 50400, while the sum is 38.

The square root of 681531257 is about 26106.1536232360. The cubic root of 681531257 is about 880.0255058895.

The spelling of 681531257 in words is "six hundred eighty-one million, five hundred thirty-one thousand, two hundred fifty-seven".