21172357926720 has 2688 divisors, whose sum is σ = 101226450124800. Its totient is φ = 4001937408000.

The previous prime is 21172357926701. The next prime is 21172357926739. The reversal of 21172357926720 is 2762975327112.

21172357926720 is a `hidden beast` number, since 2 + 1 + 1 + 7 + 2 + 3 + 579 + 2 + 67 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21172357926701) and next prime (21172357926739).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 10029538465 + ... + 10029540575.

It is an arithmetic number, because the mean of its divisors is an integer number (37658649600).

Almost surely, 2^{21172357926720} is an apocalyptic number.

21172357926720 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 21172357926720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50613225062400).

21172357926720 is an abundant number, since it is smaller than the sum of its proper divisors (80054092198080).

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

21172357926720 is a wasteful number, since it uses less digits than its factorization.

21172357926720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2250 (or 2223 counting only the distinct ones).

The product of its (nonzero) digits is 4445280, while the sum is 54.

The spelling of 21172357926720 in words is "twenty-one trillion, one hundred seventy-two billion, three hundred fifty-seven million, nine hundred twenty-six thousand, seven hundred twenty".