21653804739 has 16 divisors (see below), whose sum is σ = 33801062400. Its totient is φ = 12071807040.

The previous prime is 21653804707. The next prime is 21653804743. The reversal of 21653804739 is 93740835612.

It is not a de Polignac number, because 21653804739 - 2⁵ = 21653804707 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21653804789) 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 15 ways as a sum of consecutive naturals, for example, 12573939 + ... + 12575660.

It is an arithmetic number, because the mean of its divisors is an integer number (2112566400).

It is a 1-persistent number, because it is pandigital, but 2⋅21653804739 = 43307609478 is not.

Almost surely, 2^21653804739 is an apocalyptic number.

21653804739 is a deficient number, since it is larger than the sum of its proper divisors (12147257661).

21653804739 is a wasteful number, since it uses less digits than its factorization.

21653804739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25149650.

The product of its (nonzero) digits is 1088640, while the sum is 48.

The spelling of 21653804739 in words is "twenty-one billion, six hundred fifty-three million, eight hundred four thousand, seven hundred thirty-nine".