681447931 has 2 divisors, whose sum is σ = 681447932. Its totient is φ = 681447930.

The previous prime is 681447911. The next prime is 681447937. The reversal of 681447931 is 139744186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681447931 - 2⁷ = 681447803 is a prime.

It is a super-2 number, since 2×681447931² = 928742565328361522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (681447937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340723965 + 340723966.

It is an arithmetic number, because the mean of its divisors is an integer number (340723966).

Almost surely, 2^681447931 is an apocalyptic number.

681447931 is a deficient number, since it is larger than the sum of its proper divisors (1).

681447931 is an equidigital number, since it uses as much as digits as its factorization.

681447931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 43.

The square root of 681447931 is about 26104.5576671967. The cubic root of 681447931 is about 879.9896395991.

It can be divided in two parts, 6814 and 47931, that added together give a palindrome (54745).

The spelling of 681447931 in words is "six hundred eighty-one million, four hundred forty-seven thousand, nine hundred thirty-one".