21156264233 has 4 divisors (see below), whose sum is σ = 22783669188. Its totient is φ = 19528859280.

The previous prime is 21156264221. The next prime is 21156264277. The reversal of 21156264233 is 33246265112.

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 1368778009 + 19787486224 = 36997^2 + 140668^2 .

It is a cyclic number.

It is not a de Polignac number, because 21156264233 - 2²⁶ = 21089155369 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21156264193 and 21156264202.

It is not an unprimeable number, because it can be changed into a prime (21159264233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 813702458 + ... + 813702483.

It is an arithmetic number, because the mean of its divisors is an integer number (5695917297).

Almost surely, 2^21156264233 is an apocalyptic number.

It is an amenable number.

21156264233 is a deficient number, since it is larger than the sum of its proper divisors (1627404955).

21156264233 is a wasteful number, since it uses less digits than its factorization.

21156264233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627404954.

The product of its digits is 51840, while the sum is 35.

The spelling of 21156264233 in words is "twenty-one billion, one hundred fifty-six million, two hundred sixty-four thousand, two hundred thirty-three".