21097026720 has 1056 divisors, whose sum is σ = 96424110720. Its totient is φ = 4232632320.

The previous prime is 21097026679. The next prime is 21097026721. The reversal of 21097026720 is 2762079012.

It is a tau number, because it is divible by the number of its divisors (1056).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097026721) by changing a digit.

It is a polite number, since it can be written in 175 ways as a sum of consecutive naturals, for example, 727483666 + ... + 727483694.

Almost surely, 2^21097026720 is an apocalyptic number.

21097026720 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 21097026720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48212055360).

21097026720 is an abundant number, since it is smaller than the sum of its proper divisors (75327084000).

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

21097026720 is an equidigital number, since it uses as much as digits as its factorization.

21097026720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The spelling of 21097026720 in words is "twenty-one billion, ninety-seven million, twenty-six thousand, seven hundred twenty".