681938065251 has 12 divisors (see below), whose sum is σ = 986530114128. Its totient is φ = 453929162544.

The previous prime is 681938065247. The next prime is 681938065253. The reversal of 681938065251 is 152560839186.

681938065251 is a `hidden beast` number, since 6 + 8 + 1 + 9 + 380 + 6 + 5 + 251 = 666.

It is not a de Polignac number, because 681938065251 - 2² = 681938065247 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681938065253) 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, 58011655 + ... + 58023408.

It is an arithmetic number, because the mean of its divisors is an integer number (82210842844).

Almost surely, 2^681938065251 is an apocalyptic number.

681938065251 is a deficient number, since it is larger than the sum of its proper divisors (304592048877).

681938065251 is a wasteful number, since it uses less digits than its factorization.

681938065251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116035722 (or 116035719 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 54.

The spelling of 681938065251 in words is "six hundred eighty-one billion, nine hundred thirty-eight million, sixty-five thousand, two hundred fifty-one".