21604354737 has 16 divisors (see below), whose sum is σ = 33028165632. Its totient is φ = 12305129040.

The previous prime is 21604354727. The next prime is 21604354753. The reversal of 21604354737 is 73745340612.

It is not a de Polignac number, because 21604354737 - 2⁷ = 21604354609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21604354727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1669089 + ... + 1681982.

It is an arithmetic number, because the mean of its divisors is an integer number (2064260352).

Almost surely, 2^21604354737 is an apocalyptic number.

It is an amenable number.

21604354737 is a deficient number, since it is larger than the sum of its proper divisors (11423810895).

21604354737 is a wasteful number, since it uses less digits than its factorization.

21604354737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3351388.

The product of its (nonzero) digits is 423360, while the sum is 42.

The spelling of 21604354737 in words is "twenty-one billion, six hundred four million, three hundred fifty-four thousand, seven hundred thirty-seven".