21953008 has 80 divisors (see below), whose sum is σ = 53853696. Its totient is φ = 8421120.

The previous prime is 21952993. The next prime is 21953011. The reversal of 21953008 is 80035912.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126810 + ... + 126982.

Almost surely, 2^21953008 is an apocalyptic number.

21953008 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 21953008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26926848).

21953008 is an abundant number, since it is smaller than the sum of its proper divisors (31900688).

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

21953008 is a wasteful number, since it uses less digits than its factorization.

21953008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302 (or 296 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21953008 is about 4685.4037179308. The cubic root of 21953008 is about 280.0042856487.

The spelling of 21953008 in words is "twenty-one million, nine hundred fifty-three thousand, eight".