21204404100 has 288 divisors, whose sum is σ = 74635639680. Its totient is φ = 5121792000.

The previous prime is 21204404077. The next prime is 21204404101. The reversal of 21204404100 is 140440212.

21204404100 is a `hidden beast` number, since 2 + 120 + 440 + 4 + 100 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21204404101) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9294960 + ... + 9297240.

Almost surely, 2^21204404100 is an apocalyptic number.

21204404100 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 21204404100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37317819840).

21204404100 is an abundant number, since it is smaller than the sum of its proper divisors (53431235580).

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

21204404100 is a wasteful number, since it uses less digits than its factorization.

21204404100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2628 (or 2615 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21204404100 its reverse (140440212), we get a palindrome (21344844312).

The spelling of 21204404100 in words is "twenty-one billion, two hundred four million, four hundred four thousand, one hundred".