21120421520100 has 72 divisors (see below), whose sum is σ = 69838193833408. Its totient is φ = 4827524918400.

The previous prime is 21120421520089. The next prime is 21120421520117. The reversal of 21120421520100 is 102512402112.

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

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, 5028669691 + ... + 5028673890.

Almost surely, 2^{21120421520100} is an apocalyptic number.

21120421520100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120421520100 is an abundant number, since it is smaller than the sum of its proper divisors (48717772313308).

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

21120421520100 is a wasteful number, since it uses less digits than its factorization.

21120421520100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10057343605 (or 10057343598 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

Adding to 21120421520100 its reverse (102512402112), we get a palindrome (21222933922212).

The spelling of 21120421520100 in words is "twenty-one trillion, one hundred twenty billion, four hundred twenty-one million, five hundred twenty thousand, one hundred".