21747437051 has 4 divisors (see below), whose sum is σ = 23026698072. Its totient is φ = 20468176032.

The previous prime is 21747436967. The next prime is 21747437149. The reversal of 21747437051 is 15073474712.

It is a happy number.

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 21747437051 - 2¹⁰ = 21747436027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21747437851) 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, 639630485 + ... + 639630518.

It is an arithmetic number, because the mean of its divisors is an integer number (5756674518).

Almost surely, 2^21747437051 is an apocalyptic number.

21747437051 is a deficient number, since it is larger than the sum of its proper divisors (1279261021).

21747437051 is a wasteful number, since it uses less digits than its factorization.

21747437051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1279261020.

The product of its (nonzero) digits is 164640, while the sum is 41.

The spelling of 21747437051 in words is "twenty-one billion, seven hundred forty-seven million, four hundred thirty-seven thousand, fifty-one".