679640791 has 2 divisors, whose sum is σ = 679640792. Its totient is φ = 679640790.

The previous prime is 679640779. The next prime is 679640809. The reversal of 679640791 is 197046976.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 679640791 - 2¹³ = 679632599 is a prime.

It is a super-2 number, since 2×679640791² = 923823209582211362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (679640761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339820395 + 339820396.

It is an arithmetic number, because the mean of its divisors is an integer number (339820396).

Almost surely, 2^679640791 is an apocalyptic number.

679640791 is a deficient number, since it is larger than the sum of its proper divisors (1).

679640791 is an equidigital number, since it uses as much as digits as its factorization.

679640791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 571536, while the sum is 49.

The square root of 679640791 is about 26069.9211928230. The cubic root of 679640791 is about 879.2110659049.

The spelling of 679640791 in words is "six hundred seventy-nine million, six hundred forty thousand, seven hundred ninety-one".