21952420 has 48 divisors (see below), whose sum is σ = 54512640. Its totient is φ = 7265664.

The previous prime is 21952387. The next prime is 21952459. The reversal of 21952420 is 2425912.

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, 1357 + ... + 6763.

It is an arithmetic number, because the mean of its divisors is an integer number (1135680).

Almost surely, 2^21952420 is an apocalyptic number.

21952420 is a gapful number since it is divisible by the number (20) 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 21952420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27256320).

21952420 is an abundant number, since it is smaller than the sum of its proper divisors (32560220).

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

21952420 is a wasteful number, since it uses less digits than its factorization.

21952420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5452 (or 5450 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21952420 is about 4685.3409694493. The cubic root of 21952420 is about 280.0017857029.

The spelling of 21952420 in words is "twenty-one million, nine hundred fifty-two thousand, four hundred twenty".