690816779 has 2 divisors, whose sum is σ = 690816780. Its totient is φ = 690816778.

The previous prime is 690816761. The next prime is 690816793. The reversal of 690816779 is 977618096.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 690816779 - 2²⁴ = 674039563 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 690816779.

It is not a weakly prime, because it can be changed into another prime (690816179) 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, 345408389 + 345408390.

It is an arithmetic number, because the mean of its divisors is an integer number (345408390).

Almost surely, 2^690816779 is an apocalyptic number.

690816779 is a deficient number, since it is larger than the sum of its proper divisors (1).

690816779 is an equidigital number, since it uses as much as digits as its factorization.

690816779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1143072, while the sum is 53.

The square root of 690816779 is about 26283.3935974790. The cubic root of 690816779 is about 884.0041268925.

The spelling of 690816779 in words is "six hundred ninety million, eight hundred sixteen thousand, seven hundred seventy-nine".