21529718952 has 256 divisors, whose sum is σ = 67765248000. Its totient is φ = 5559570432.

The previous prime is 21529718941. The next prime is 21529718971. The reversal of 21529718952 is 25981792512.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a junction number, because it is equal to n+sod(n) for n = 21529718895 and 21529718904.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8346799 + ... + 8349377.

It is an arithmetic number, because the mean of its divisors is an integer number (264708000).

Almost surely, 2^21529718952 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 21529718952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33882624000).

21529718952 is an abundant number, since it is smaller than the sum of its proper divisors (46235529048).

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

21529718952 is a wasteful number, since it uses less digits than its factorization.

21529718952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2728 (or 2724 counting only the distinct ones).

The product of its digits is 907200, while the sum is 51.

The spelling of 21529718952 in words is "twenty-one billion, five hundred twenty-nine million, seven hundred eighteen thousand, nine hundred fifty-two".