21943908 has 108 divisors (see below), whose sum is σ = 66696448. Its totient is φ = 5952960.

The previous prime is 21943903. The next prime is 21943913. The reversal of 21943908 is 80934912.

21943908 is a `hidden beast` number, since 219 + 439 + 0 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21943903) and next prime (21943913).

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

It is not an unprimeable number, because it can be changed into a prime (21943903) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 414010 + ... + 414062.

Almost surely, 2^21943908 is an apocalyptic number.

21943908 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 21943908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33348224).

21943908 is an abundant number, since it is smaller than the sum of its proper divisors (44752540).

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

21943908 is a wasteful number, since it uses less digits than its factorization.

21943908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 96 counting only the distinct ones).

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

The square root of 21943908 is about 4684.4325163247. The cubic root of 21943908 is about 279.9655910098.

The spelling of 21943908 in words is "twenty-one million, nine hundred forty-three thousand, nine hundred eight".