21621544344510 has 128 divisors (see below), whose sum is σ = 57996263098368. Its totient is φ = 5113176960000.

The previous prime is 21621544344467. The next prime is 21621544344511. The reversal of 21621544344510 is 1544344512612.

It is a super-2 number, since 2×21621544344510² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621544344511) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 129141372 + ... + 129308688.

It is an arithmetic number, because the mean of its divisors is an integer number (453095805456).

Almost surely, 2^{21621544344510} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21621544344510, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28998131549184).

21621544344510 is an abundant number, since it is smaller than the sum of its proper divisors (36374718753858).

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

21621544344510 is a wasteful number, since it uses less digits than its factorization.

21621544344510 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176930.

The product of its (nonzero) digits is 460800, while the sum is 42.

The spelling of 21621544344510 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred forty-four million, three hundred forty-four thousand, five hundred ten".