21642660972000 has 384 divisors, whose sum is σ = 79559318966400. Its totient is φ = 5714231040000.

The previous prime is 21642660971977. The next prime is 21642660972059. The reversal of 21642660972000 is 27906624612.

21642660972000 is a `hidden beast` number, since 2 + 16 + 4 + 2 + 6 + 609 + 7 + 20 + 0 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9915946 + ... + 11900054.

It is an arithmetic number, because the mean of its divisors is an integer number (207185726475).

Almost surely, 2^{21642660972000} is an apocalyptic number.

21642660972000 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 21642660972000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39779659483200).

21642660972000 is an abundant number, since it is smaller than the sum of its proper divisors (57916657994400).

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

21642660972000 is a wasteful number, since it uses less digits than its factorization.

21642660972000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1984244 (or 1984220 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 21642660972000 in words is "twenty-one trillion, six hundred forty-two billion, six hundred sixty million, nine hundred seventy-two thousand".