21500102400 has 324 divisors, whose sum is σ = 82542888792. Its totient is φ = 4914094080.

The previous prime is 21500102279. The next prime is 21500102411. The reversal of 21500102400 is 420100512.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21500102400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 929374 + ... + 952226.

Almost surely, 2^21500102400 is an apocalyptic number.

21500102400 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 21500102400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41271444396).

21500102400 is an abundant number, since it is smaller than the sum of its proper divisors (61042786392).

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

21500102400 is a wasteful number, since it uses less digits than its factorization.

21500102400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22896 (or 22870 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

Adding to 21500102400 its reverse (420100512), we get a palindrome (21920202912).

It can be divided in two parts, 21 and 500102400, that multiplied together give a square (10502150400 = 102480²).

The spelling of 21500102400 in words is "twenty-one billion, five hundred million, one hundred two thousand, four hundred".