691066979 has 2 divisors, whose sum is σ = 691066980. Its totient is φ = 691066978.

The previous prime is 691066969. The next prime is 691067023. The reversal of 691066979 is 979660196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691066979 - 2²⁰ = 690018403 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 691066979.

It is not a weakly prime, because it can be changed into another prime (691066919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345533489 + 345533490.

It is an arithmetic number, because the mean of its divisors is an integer number (345533490).

Almost surely, 2^691066979 is an apocalyptic number.

691066979 is a deficient number, since it is larger than the sum of its proper divisors (1).

691066979 is an equidigital number, since it uses as much as digits as its factorization.

691066979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1102248, while the sum is 53.

The square root of 691066979 is about 26288.1528259404. The cubic root of 691066979 is about 884.1108368734.

The spelling of 691066979 in words is "six hundred ninety-one million, sixty-six thousand, nine hundred seventy-nine".