21204025500 has 192 divisors, whose sum is σ = 70791791616. Its totient is φ = 4831200000.

The previous prime is 21204025477. The next prime is 21204025529. The reversal of 21204025500 is 552040212.

It is a happy number.

It is a super-2 number, since 2×21204025500² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 3472450 + ... + 3478550.

It is an arithmetic number, because the mean of its divisors is an integer number (368707248).

Almost surely, 2^21204025500 is an apocalyptic number.

21204025500 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 21204025500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35395895808).

21204025500 is an abundant number, since it is smaller than the sum of its proper divisors (49587766116).

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

21204025500 is a wasteful number, since it uses less digits than its factorization.

21204025500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6461 (or 6449 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

Adding to 21204025500 its reverse (552040212), we get a palindrome (21756065712).

The spelling of 21204025500 in words is "twenty-one billion, two hundred four million, twenty-five thousand, five hundred".