678643731 has 32 divisors (see below), whose sum is σ = 1018617600. Its totient is φ = 446523840.

The previous prime is 678643711. The next prime is 678643739. The reversal of 678643731 is 137346876.

It is not a de Polignac number, because 678643731 - 2⁵ = 678643699 is a prime.

It is a super-2 number, since 2×678643731² = 921114627251200722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (678643739) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 791455 + ... + 792311.

It is an arithmetic number, because the mean of its divisors is an integer number (31831800).

Almost surely, 2^678643731 is an apocalyptic number.

678643731 is a deficient number, since it is larger than the sum of its proper divisors (339973869).

678643731 is a wasteful number, since it uses less digits than its factorization.

678643731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1216 (or 1210 counting only the distinct ones).

The product of its digits is 508032, while the sum is 45.

The square root of 678643731 is about 26050.7913699373. The cubic root of 678643731 is about 878.7809096476.

The spelling of 678643731 in words is "six hundred seventy-eight million, six hundred forty-three thousand, seven hundred thirty-one".