690691979 has 2 divisors, whose sum is σ = 690691980. Its totient is φ = 690691978.

The previous prime is 690691957. The next prime is 690692003. The reversal of 690691979 is 979196096.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690691979 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (690691949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345345989 + 345345990.

It is an arithmetic number, because the mean of its divisors is an integer number (345345990).

Almost surely, 2^690691979 is an apocalyptic number.

690691979 is a deficient number, since it is larger than the sum of its proper divisors (1).

690691979 is an equidigital number, since it uses as much as digits as its factorization.

690691979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1653372, while the sum is 56.

The square root of 690691979 is about 26281.0193675968. The cubic root of 690691979 is about 883.9508902204.

The spelling of 690691979 in words is "six hundred ninety million, six hundred ninety-one thousand, nine hundred seventy-nine".