2556964561 has 4 divisors (see below), whose sum is σ = 2565186624. Its totient is φ = 2548742500.

The previous prime is 2556964541. The next prime is 2556964567. The reversal of 2556964561 is 1654696552.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2556964561 - 2⁹ = 2556964049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556964567) 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, 4110565 + ... + 4111186.

It is an arithmetic number, because the mean of its divisors is an integer number (641296656).

Almost surely, 2^2556964561 is an apocalyptic number.

It is an amenable number.

2556964561 is a deficient number, since it is larger than the sum of its proper divisors (8222063).

2556964561 is an equidigital number, since it uses as much as digits as its factorization.

2556964561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8222062.

The product of its digits is 1944000, while the sum is 49.

The square root of 2556964561 is about 50566.4371001161. The cubic root of 2556964561 is about 1367.4398635360.

The spelling of 2556964561 in words is "two billion, five hundred fifty-six million, nine hundred sixty-four thousand, five hundred sixty-one".