21256044565029 has 4 divisors (see below), whose sum is σ = 28341392753376. Its totient is φ = 14170696376684.

The previous prime is 21256044564977. The next prime is 21256044565051. The reversal of 21256044565029 is 92056544065212.

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 21256044565029 - 2⁷ = 21256044564901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256044567029) 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, 3542674094169 + ... + 3542674094174.

It is an arithmetic number, because the mean of its divisors is an integer number (7085348188344).

Almost surely, 2^{21256044565029} is an apocalyptic number.

It is an amenable number.

21256044565029 is a deficient number, since it is larger than the sum of its proper divisors (7085348188347).

21256044565029 is an equidigital number, since it uses as much as digits as its factorization.

21256044565029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7085348188346.

The product of its (nonzero) digits is 5184000, while the sum is 51.

The spelling of 21256044565029 in words is "twenty-one trillion, two hundred fifty-six billion, forty-four million, five hundred sixty-five thousand, twenty-nine".