6556751581 has 4 divisors (see below), whose sum is σ = 6635748672. Its totient is φ = 6477754492.

The previous prime is 6556751543. The next prime is 6556751599. The reversal of 6556751581 is 1851576556.

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 a de Polignac number, because none of the positive numbers 2^k-6556751581 is a prime.

It is a super-2 number, since 2×6556751581² = 85981982589891999122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6556751081) 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, 39498421 + ... + 39498586.

It is an arithmetic number, because the mean of its divisors is an integer number (1658937168).

Almost surely, 2^6556751581 is an apocalyptic number.

It is an amenable number.

6556751581 is a deficient number, since it is larger than the sum of its proper divisors (78997091).

6556751581 is an equidigital number, since it uses as much as digits as its factorization.

6556751581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78997090.

The product of its digits is 1260000, while the sum is 49.

The square root of 6556751581 is about 80973.7709446707. The cubic root of 6556751581 is about 1871.6712809053.

The spelling of 6556751581 in words is "six billion, five hundred fifty-six million, seven hundred fifty-one thousand, five hundred eighty-one".