21655432401 has 16 divisors (see below), whose sum is σ = 29568650496. Its totient is φ = 14090113296.

The previous prime is 21655432297. The next prime is 21655432411. The reversal of 21655432401 is 10423455612.

It is not a de Polignac number, because 21655432401 - 2¹⁷ = 21655301329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21655432411) 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, 100086 + ... + 230928.

It is an arithmetic number, because the mean of its divisors is an integer number (1848040656).

Almost surely, 2^21655432401 is an apocalyptic number.

It is an amenable number.

21655432401 is a deficient number, since it is larger than the sum of its proper divisors (7913218095).

21655432401 is a wasteful number, since it uses less digits than its factorization.

21655432401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132172.

The product of its (nonzero) digits is 28800, while the sum is 33.

The spelling of 21655432401 in words is "twenty-one billion, six hundred fifty-five million, four hundred thirty-two thousand, four hundred one".