2656666321 has 4 divisors (see below), whose sum is σ = 2657326500. Its totient is φ = 2656006144.

The previous prime is 2656666283. The next prime is 2656666339. The reversal of 2656666321 is 1236666562.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1594884096 + 1061782225 = 39936^2 + 32585^2 .

It is a cyclic number.

It is not a de Polignac number, because 2656666321 - 2¹⁷ = 2656535249 is a prime.

It is a super-2 number, since 2×2656666321² = 14115751882271350082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2656666021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 324016 + ... + 332113.

It is an arithmetic number, because the mean of its divisors is an integer number (664331625).

Almost surely, 2^2656666321 is an apocalyptic number.

It is an amenable number.

2656666321 is a deficient number, since it is larger than the sum of its proper divisors (660179).

2656666321 is an equidigital number, since it uses as much as digits as its factorization.

2656666321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660178.

The product of its digits is 466560, while the sum is 43.

The square root of 2656666321 is about 51542.8590689341. The cubic root of 2656666321 is about 1384.9869141678.

The spelling of 2656666321 in words is "two billion, six hundred fifty-six million, six hundred sixty-six thousand, three hundred twenty-one".