21756004405 has 32 divisors (see below), whose sum is σ = 29192534784. Its totient is φ = 15479878656.

The previous prime is 21756004351. The next prime is 21756004411. The reversal of 21756004405 is 50440065712.

It is a cyclic number.

It is not a de Polignac number, because 21756004405 - 2¹⁵ = 21755971637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 95227 + ... + 229303.

It is an arithmetic number, because the mean of its divisors is an integer number (912266712).

Almost surely, 2^21756004405 is an apocalyptic number.

It is an amenable number.

21756004405 is a deficient number, since it is larger than the sum of its proper divisors (7436530379).

21756004405 is a wasteful number, since it uses less digits than its factorization.

21756004405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134205.

The product of its (nonzero) digits is 33600, while the sum is 34.

The spelling of 21756004405 in words is "twenty-one billion, seven hundred fifty-six million, four thousand, four hundred five".