656049978989 has 2 divisors, whose sum is σ = 656049978990. Its totient is φ = 656049978988.

The previous prime is 656049978953. The next prime is 656049979009. The reversal of 656049978989 is 989879940656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 524055822889 + 131994156100 = 723917^2 + 363310^2 .

It is a cyclic number.

It is not a de Polignac number, because 656049978989 - 2²⁸ = 655781543533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (656049978929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328024989494 + 328024989495.

It is an arithmetic number, because the mean of its divisors is an integer number (328024989495).

Almost surely, 2^656049978989 is an apocalyptic number.

It is an amenable number.

656049978989 is a deficient number, since it is larger than the sum of its proper divisors (1).

656049978989 is an equidigital number, since it uses as much as digits as its factorization.

656049978989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2116316160, while the sum is 80.

The spelling of 656049978989 in words is "six hundred fifty-six billion, forty-nine million, nine hundred seventy-eight thousand, nine hundred eighty-nine".