21807121481264 has 640 divisors, whose sum is σ = 54922199040000. Its totient is φ = 8352155814912.

The previous prime is 21807121481261. The next prime is 21807121481267. The reversal of 21807121481264 is 46218412170812.

It is an interprime number because it is at equal distance from previous prime (21807121481261) and next prime (21807121481267).

It is a Harshad number since it is a multiple of its sum of digits (47).

It is not an unprimeable number, because it can be changed into a prime (21807121481261) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 15324750857 + ... + 15324752279.

It is an arithmetic number, because the mean of its divisors is an integer number (85815936000).

Almost surely, 2^{21807121481264} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21807121481264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27461099520000).

21807121481264 is an abundant number, since it is smaller than the sum of its proper divisors (33115077558736).

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

21807121481264 is a wasteful number, since it uses less digits than its factorization.

21807121481264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630 (or 1610 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 47.

The spelling of 21807121481264 in words is "twenty-one trillion, eight hundred seven billion, one hundred twenty-one million, four hundred eighty-one thousand, two hundred sixty-four".