21894168408 has 64 divisors (see below), whose sum is σ = 62569032960. Its totient is φ = 6254050176.

The previous prime is 21894168389. The next prime is 21894168409. The reversal of 21894168408 is 80486149812.

It is a super-2 number, since 2×21894168408² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21894168409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 886110 + ... + 910482.

It is an arithmetic number, because the mean of its divisors is an integer number (977641140).

Almost surely, 2^21894168408 is an apocalyptic number.

21894168408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21894168408 is an abundant number, since it is smaller than the sum of its proper divisors (40674864552).

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

21894168408 is a wasteful number, since it uses less digits than its factorization.

21894168408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29736 (or 29732 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 51.

The spelling of 21894168408 in words is "twenty-one billion, eight hundred ninety-four million, one hundred sixty-eight thousand, four hundred eight".