2656669921 has 2 divisors, whose sum is σ = 2656669922. Its totient is φ = 2656669920.

The previous prime is 2656669871. The next prime is 2656669933. The reversal of 2656669921 is 1299666562.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1826365696 + 830304225 = 42736^2 + 28815^2 .

It is a cyclic number.

It is not a de Polignac number, because 2656669921 - 2¹⁷ = 2656538849 is a prime.

It is a super-2 number, since 2×2656669921² = 14115790138292292482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2656669021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1328334960 + 1328334961.

It is an arithmetic number, because the mean of its divisors is an integer number (1328334961).

Almost surely, 2^2656669921 is an apocalyptic number.

It is an amenable number.

2656669921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2656669921 is an equidigital number, since it uses as much as digits as its factorization.

2656669921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2099520, while the sum is 52.

The square root of 2656669921 is about 51542.8939913156. The cubic root of 2656669921 is about 1384.9875397577.

The spelling of 2656669921 in words is "two billion, six hundred fifty-six million, six hundred sixty-nine thousand, nine hundred twenty-one".