21615411552 has 144 divisors (see below), whose sum is σ = 66611326320. Its totient is φ = 6119027712.

The previous prime is 21615411487. The next prime is 21615411563. The reversal of 21615411552 is 25511451612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 491658 + ... + 533814.

It is an arithmetic number, because the mean of its divisors is an integer number (462578655).

Almost surely, 2^21615411552 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 21615411552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33305663160).

21615411552 is an abundant number, since it is smaller than the sum of its proper divisors (44995914768).

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

21615411552 is a wasteful number, since it uses less digits than its factorization.

21615411552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42293 (or 42278 counting only the distinct ones).

The product of its digits is 12000, while the sum is 33.

The spelling of 21615411552 in words is "twenty-one billion, six hundred fifteen million, four hundred eleven thousand, five hundred fifty-two".