21015507097552 has 320 divisors, whose sum is σ = 49347780968448. Its totient is φ = 8558032896000.

The previous prime is 21015507097549. The next prime is 21015507097577. The reversal of 21015507097552 is 25579070551012.

It is a junction number, because it is equal to n+sod(n) for n = 21015507097496 and 21015507097505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3009520653 + ... + 3009527635.

Almost surely, 2^{21015507097552} is an apocalyptic number.

21015507097552 is a gapful number since it is divisible by the number (22) 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 21015507097552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24673890484224).

21015507097552 is an abundant number, since it is smaller than the sum of its proper divisors (28332273870896).

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

21015507097552 is a wasteful number, since it uses less digits than its factorization.

21015507097552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7578 (or 7572 counting only the distinct ones).

The product of its (nonzero) digits is 1102500, while the sum is 49.

The spelling of 21015507097552 in words is "twenty-one trillion, fifteen billion, five hundred seven million, ninety-seven thousand, five hundred fifty-two".