21450012100 has 72 divisors (see below), whose sum is σ = 50942114496. Its totient is φ = 7774800000.

The previous prime is 21450012079. The next prime is 21450012127. The reversal of 21450012100 is 121005412.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 310750 + ... + 373450.

It is an arithmetic number, because the mean of its divisors is an integer number (707529368).

Almost surely, 2^21450012100 is an apocalyptic number.

21450012100 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 21450012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25471057248).

21450012100 is an abundant number, since it is smaller than the sum of its proper divisors (29492102396).

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

21450012100 is a wasteful number, since it uses less digits than its factorization.

21450012100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63037 (or 63030 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

Adding to 21450012100 its reverse (121005412), we get a palindrome (21571017512).

The spelling of 21450012100 in words is "twenty-one billion, four hundred fifty million, twelve thousand, one hundred".