21134172672 has 240 divisors, whose sum is σ = 64977424512. Its totient is φ = 6852833280.

The previous prime is 21134172649. The next prime is 21134172691. The reversal of 21134172672 is 27627143112.

21134172672 is a `hidden beast` number, since 211 + 3 + 417 + 26 + 7 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4601097 + ... + 4605687.

Almost surely, 2^21134172672 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21134172672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32488712256).

21134172672 is an abundant number, since it is smaller than the sum of its proper divisors (43843251840).

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

21134172672 is an frugal number, since it uses more digits than its factorization.

21134172672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4661 (or 4633 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The spelling of 21134172672 in words is "twenty-one billion, one hundred thirty-four million, one hundred seventy-two thousand, six hundred seventy-two".