21621463402560 has 448 divisors, whose sum is σ = 79466070988800. Its totient is φ = 4878542389248.

The previous prime is 21621463402507. The next prime is 21621463402571. The reversal of 21621463402560 is 6520436412612.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×21621463402560² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 370182319 + ... + 370240721.

Almost surely, 2^{21621463402560} is an apocalyptic number.

21621463402560 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 21621463402560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39733035494400).

21621463402560 is an abundant number, since it is smaller than the sum of its proper divisors (57844607586240).

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

21621463402560 is a wasteful number, since it uses less digits than its factorization.

21621463402560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59138 (or 59128 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 42.

The spelling of 21621463402560 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred sixty-three million, four hundred two thousand, five hundred sixty".