21721767040512 has 720 divisors, whose sum is σ = 79637814416160. Its totient is φ = 5578534748160.

The previous prime is 21721767040487. The next prime is 21721767040513. The reversal of 21721767040512 is 21504076712712.

It is a happy number.

21721767040512 is a `hidden beast` number, since 2 + 1 + 7 + 2 + 176 + 70 + 405 + 1 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21721767040513) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 347333598 + ... + 347396130.

It is an arithmetic number, because the mean of its divisors is an integer number (110608075578).

Almost surely, 2^{21721767040512} is an apocalyptic number.

21721767040512 is a gapful number since it is divisible by the number (22) 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 21721767040512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39818907208080).

21721767040512 is an abundant number, since it is smaller than the sum of its proper divisors (57916047375648).

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

21721767040512 is a wasteful number, since it uses less digits than its factorization.

21721767040512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62675 (or 62645 counting only the distinct ones).

The product of its (nonzero) digits is 329280, while the sum is 45.

The spelling of 21721767040512 in words is "twenty-one trillion, seven hundred twenty-one billion, seven hundred sixty-seven million, forty thousand, five hundred twelve".