21243056051 has 4 divisors (see below), whose sum is σ = 24277778352. Its totient is φ = 18208333752.

The previous prime is 21243056033. The next prime is 21243056071. The reversal of 21243056051 is 15065034212.

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

It is not a de Polignac number, because 21243056051 - 2³⁰ = 20169314227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243056071) 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, 1517361140 + ... + 1517361153.

It is an arithmetic number, because the mean of its divisors is an integer number (6069444588).

Almost surely, 2^21243056051 is an apocalyptic number.

21243056051 is a deficient number, since it is larger than the sum of its proper divisors (3034722301).

21243056051 is an equidigital number, since it uses as much as digits as its factorization.

21243056051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3034722300.

The product of its (nonzero) digits is 7200, while the sum is 29.

The spelling of 21243056051 in words is "twenty-one billion, two hundred forty-three million, fifty-six thousand, fifty-one".