21621122406 has 24 divisors (see below), whose sum is σ = 50449286160. Its totient is φ = 6652652976.

The previous prime is 21621122401. The next prime is 21621122459. The reversal of 21621122406 is 60422112612.

21621122406 is a `hidden beast` number, since 2 + 1 + 621 + 12 + 24 + 0 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21621122406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621122401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 46198746 + ... + 46199213.

It is an arithmetic number, because the mean of its divisors is an integer number (2102053590).

Almost surely, 2^21621122406 is an apocalyptic number.

21621122406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21621122406 is an abundant number, since it is smaller than the sum of its proper divisors (28828163754).

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

21621122406 is a wasteful number, since it uses less digits than its factorization.

21621122406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92397980 (or 92397977 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The spelling of 21621122406 in words is "twenty-one billion, six hundred twenty-one million, one hundred twenty-two thousand, four hundred six".