21216052500 has 120 divisors (see below), whose sum is σ = 62785127328. Its totient is φ = 5573040000.

The previous prime is 21216052499. The next prime is 21216052523. The reversal of 21216052500 is 525061212.

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 39 ways as a sum of consecutive naturals, for example, 481390 + ... + 523610.

Almost surely, 2^21216052500 is an apocalyptic number.

21216052500 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 21216052500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31392563664).

21216052500 is an abundant number, since it is smaller than the sum of its proper divisors (41569074828).

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

21216052500 is a wasteful number, since it uses less digits than its factorization.

21216052500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42315 (or 42298 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The spelling of 21216052500 in words is "twenty-one billion, two hundred sixteen million, fifty-two thousand, five hundred".