21570056051 has 4 divisors (see below), whose sum is σ = 21611299512. Its totient is φ = 21528812592.

The previous prime is 21570056009. The next prime is 21570056069. The reversal of 21570056051 is 15065007512.

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

It is a cyclic number.

It is not a de Polignac number, because 21570056051 - 2²² = 21565861747 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21570055999 and 21570056017.

It is not an unprimeable number, because it can be changed into a prime (21570052051) 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, 20620946 + ... + 20621991.

It is an arithmetic number, because the mean of its divisors is an integer number (5402824878).

Almost surely, 2^21570056051 is an apocalyptic number.

21570056051 is a deficient number, since it is larger than the sum of its proper divisors (41243461).

21570056051 is an equidigital number, since it uses as much as digits as its factorization.

21570056051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41243460.

The product of its (nonzero) digits is 10500, while the sum is 32.

The spelling of 21570056051 in words is "twenty-one billion, five hundred seventy million, fifty-six thousand, fifty-one".