681839731 has 2 divisors, whose sum is σ = 681839732. Its totient is φ = 681839730.

The previous prime is 681839713. The next prime is 681839747. The reversal of 681839731 is 137938186.

Together with previous prime (681839713) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681839731 - 2²⁹ = 144968819 is a prime.

It is a super-2 number, since 2×681839731² = 929810837540304722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (681839131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340919865 + 340919866.

It is an arithmetic number, because the mean of its divisors is an integer number (340919866).

Almost surely, 2^681839731 is an apocalyptic number.

681839731 is a deficient number, since it is larger than the sum of its proper divisors (1).

681839731 is an equidigital number, since it uses as much as digits as its factorization.

681839731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 46.

The square root of 681839731 is about 26112.0610255108. The cubic root of 681839731 is about 880.1582579527.

The spelling of 681839731 in words is "six hundred eighty-one million, eight hundred thirty-nine thousand, seven hundred thirty-one".