21498732720 has 320 divisors, whose sum is σ = 75423744000. Its totient is φ = 5627833344.

The previous prime is 21498732709. The next prime is 21498732721. The reversal of 21498732720 is 2723789412.

21498732720 is a `hidden beast` number, since 21 + 498 + 73 + 2 + 72 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21498732721) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 29900521 + ... + 29901239.

It is an arithmetic number, because the mean of its divisors is an integer number (235699200).

Almost surely, 2^21498732720 is an apocalyptic number.

21498732720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21498732720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37711872000).

21498732720 is an abundant number, since it is smaller than the sum of its proper divisors (53925011280).

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

21498732720 is a wasteful number, since it uses less digits than its factorization.

21498732720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 977 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The spelling of 21498732720 in words is "twenty-one billion, four hundred ninety-eight million, seven hundred thirty-two thousand, seven hundred twenty".