678940691 has 16 divisors (see below), whose sum is σ = 802743648. Its totient is φ = 566092800.

The previous prime is 678940687. The next prime is 678940697. The reversal of 678940691 is 196049876.

It is not a de Polignac number, because 678940691 - 2² = 678940687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678940697) 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, 7331 + ... + 37571.

It is an arithmetic number, because the mean of its divisors is an integer number (50171478).

Almost surely, 2^678940691 is an apocalyptic number.

678940691 is a deficient number, since it is larger than the sum of its proper divisors (123802957).

678940691 is a wasteful number, since it uses less digits than its factorization.

678940691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30422.

The product of its (nonzero) digits is 653184, while the sum is 50.

The square root of 678940691 is about 26056.4903814769. The cubic root of 678940691 is about 878.9090695408.

The spelling of 678940691 in words is "six hundred seventy-eight million, nine hundred forty thousand, six hundred ninety-one".