21604034881 has 32 divisors (see below), whose sum is σ = 26233159680. Its totient is φ = 17522049600.

The previous prime is 21604034831. The next prime is 21604034887. The reversal of 21604034881 is 18843040612.

It is not a de Polignac number, because 21604034881 - 2¹⁷ = 21603903809 is a prime.

It is a super-2 number, since 2×21604034881² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21604034881.

It is not an unprimeable number, because it can be changed into a prime (21604034887) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4071276 + ... + 4076578.

It is an arithmetic number, because the mean of its divisors is an integer number (819786240).

Almost surely, 2^21604034881 is an apocalyptic number.

It is an amenable number.

21604034881 is a deficient number, since it is larger than the sum of its proper divisors (4629124799).

21604034881 is a wasteful number, since it uses less digits than its factorization.

21604034881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6277.

The product of its (nonzero) digits is 36864, while the sum is 37.

The spelling of 21604034881 in words is "twenty-one billion, six hundred four million, thirty-four thousand, eight hundred eighty-one".