21123919724544 has 1440 divisors, whose sum is σ = 77912590386176. Its totient is φ = 5366171566080.

The previous prime is 21123919724539. The next prime is 21123919724563. The reversal of 21123919724544 is 44542791932112.

21123919724544 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 3 + 9 + 1 + 97 + 2 + 4 + 544 = 666.

It is a super-3 number, since 3×21123919724544³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 77948043129 + ... + 77948043399.

Almost surely, 2^{21123919724544} is an apocalyptic number.

21123919724544 is a gapful number since it is divisible by the number (24) 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 21123919724544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38956295193088).

21123919724544 is an abundant number, since it is smaller than the sum of its proper divisors (56788670661632).

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

21123919724544 is a wasteful number, since it uses less digits than its factorization.

21123919724544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519 (or 490 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The spelling of 21123919724544 in words is "twenty-one trillion, one hundred twenty-three billion, nine hundred nineteen million, seven hundred twenty-four thousand, five hundred forty-four".