21354650172 has 18 divisors (see below), whose sum is σ = 53979810248. Its totient is φ = 7118216712.

The previous prime is 21354650171. The next prime is 21354650209. The reversal of 21354650172 is 27105645312.

21354650172 is a `hidden beast` number, since 21 + 3 + 5 + 465 + 0 + 172 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 593184727 = 21354650172 / (2 + 1 + 3 + 5 + 4 + 6 + 5 + 0 + 1 + 7 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21354650171) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 296592328 + ... + 296592399.

Almost surely, 2^21354650172 is an apocalyptic number.

It is an amenable number.

21354650172 is an abundant number, since it is smaller than the sum of its proper divisors (32625160076).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21354650172 is a wasteful number, since it uses less digits than its factorization.

21354650172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593184737 (or 593184732 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 21354650172 in words is "twenty-one billion, three hundred fifty-four million, six hundred fifty thousand, one hundred seventy-two".