21156344353 has 4 divisors (see below), whose sum is σ = 21158152240. Its totient is φ = 21154536468.

The previous prime is 21156344347. The next prime is 21156344369. The reversal of 21156344353 is 35344365112.

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 21156344353 - 2²⁵ = 21122789921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21156144353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 886275 + ... + 909832.

It is an arithmetic number, because the mean of its divisors is an integer number (5289538060).

Almost surely, 2^21156344353 is an apocalyptic number.

It is an amenable number.

21156344353 is a deficient number, since it is larger than the sum of its proper divisors (1807887).

21156344353 is a wasteful number, since it uses less digits than its factorization.

21156344353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1807886.

The product of its digits is 129600, while the sum is 37.

The spelling of 21156344353 in words is "twenty-one billion, one hundred fifty-six million, three hundred forty-four thousand, three hundred fifty-three".