21994308 has 96 divisors (see below), whose sum is σ = 66662400. Its totient is φ = 6140448.

The previous prime is 21994237. The next prime is 21994319. The reversal of 21994308 is 80349912.

21994308 is a `hidden beast` number, since 219 + 9 + 430 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35223 + ... + 35841.

It is an arithmetic number, because the mean of its divisors is an integer number (694400).

Almost surely, 2^21994308 is an apocalyptic number.

21994308 is a gapful number since it is divisible by the number (28) 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 21994308, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33331200).

21994308 is an abundant number, since it is smaller than the sum of its proper divisors (44668092).

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

21994308 is a wasteful number, since it uses less digits than its factorization.

21994308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 21994308 is about 4689.8089513327. The cubic root of 21994308 is about 280.1797655147.

The spelling of 21994308 in words is "twenty-one million, nine hundred ninety-four thousand, three hundred eight".