2556325661 has 4 divisors (see below), whose sum is σ = 2579778300. Its totient is φ = 2532873024.

The previous prime is 2556325657. The next prime is 2556325679. The reversal of 2556325661 is 1665236552.

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 1438760761 + 1117564900 = 37931^2 + 33430^2 .

It is a cyclic number.

It is not a de Polignac number, because 2556325661 - 2² = 2556325657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2556325691) 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, 11726156 + ... + 11726373.

It is an arithmetic number, because the mean of its divisors is an integer number (644944575).

Almost surely, 2^2556325661 is an apocalyptic number.

It is an amenable number.

2556325661 is a deficient number, since it is larger than the sum of its proper divisors (23452639).

2556325661 is a wasteful number, since it uses less digits than its factorization.

2556325661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23452638.

The product of its digits is 324000, while the sum is 41.

The square root of 2556325661 is about 50560.1192739891. The cubic root of 2556325661 is about 1367.3259615396.

The spelling of 2556325661 in words is "two billion, five hundred fifty-six million, three hundred twenty-five thousand, six hundred sixty-one".