6690815977 has 2 divisors, whose sum is σ = 6690815978. Its totient is φ = 6690815976.

The previous prime is 6690815951. The next prime is 6690816019. The reversal of 6690815977 is 7795180966.

6690815977 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5076705001 + 1614110976 = 71251^2 + 40176^2 .

It is a cyclic number.

It is not a de Polignac number, because 6690815977 - 2⁷ = 6690815849 is a prime.

It is not a weakly prime, because it can be changed into another prime (6690819977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3345407988 + 3345407989.

It is an arithmetic number, because the mean of its divisors is an integer number (3345407989).

Almost surely, 2^6690815977 is an apocalyptic number.

It is an amenable number.

6690815977 is a deficient number, since it is larger than the sum of its proper divisors (1).

6690815977 is an equidigital number, since it uses as much as digits as its factorization.

6690815977 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5715360, while the sum is 58.

The square root of 6690815977 is about 81797.4081313094. The cubic root of 6690815977 is about 1884.3418563704.

The spelling of 6690815977 in words is "six billion, six hundred ninety million, eight hundred fifteen thousand, nine hundred seventy-seven".