21621007104 has 36 divisors (see below), whose sum is σ = 57543411576. Its totient is φ = 7207002112.

The previous prime is 21621007087. The next prime is 21621007139. The reversal of 21621007104 is 40170012612.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14075409 + ... + 14076944.

Almost surely, 2^21621007104 is an apocalyptic number.

21621007104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21621007104 is an abundant number, since it is smaller than the sum of its proper divisors (35922404472).

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

21621007104 is an equidigital number, since it uses as much as digits as its factorization.

21621007104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28152372 (or 28152358 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

Adding to 21621007104 its reverse (40170012612), we get a palindrome (61791019716).

The spelling of 21621007104 in words is "twenty-one billion, six hundred twenty-one million, seven thousand, one hundred four".