21107521500 has 192 divisors, whose sum is σ = 66684788352. Its totient is φ = 5157120000.

The previous prime is 21107521451. The next prime is 21107521531. The reversal of 21107521500 is 512570112.

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, 2667550 + ... + 2675450.

It is an arithmetic number, because the mean of its divisors is an integer number (347316606).

Almost surely, 2^21107521500 is an apocalyptic number.

21107521500 is a gapful number since it is divisible by the number (20) 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 21107521500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33342394176).

21107521500 is an abundant number, since it is smaller than the sum of its proper divisors (45577266852).

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

21107521500 is a wasteful number, since it uses less digits than its factorization.

21107521500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8073 (or 8061 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 24.

The spelling of 21107521500 in words is "twenty-one billion, one hundred seven million, five hundred twenty-one thousand, five hundred".