21908152 has 16 divisors (see below), whose sum is σ = 46946160. Its totient is φ = 9389184.

The previous prime is 21908147. The next prime is 21908177. The reversal of 21908152 is 25180912.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21908152.

It is a congruent number.

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, 195553 + ... + 195664.

It is an arithmetic number, because the mean of its divisors is an integer number (2934135).

Almost surely, 2^21908152 is an apocalyptic number.

It is an amenable number.

21908152 is an abundant number, since it is smaller than the sum of its proper divisors (25038008).

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

21908152 is a wasteful number, since it uses less digits than its factorization.

21908152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391230 (or 391226 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21908152 is about 4680.6144895729. The cubic root of 21908152 is about 279.8134471635.

The spelling of 21908152 in words is "twenty-one million, nine hundred eight thousand, one hundred fifty-two".