21422520 has 96 divisors (see below), whose sum is σ = 79578720. Its totient is φ = 4896000.

The previous prime is 21422501. The next prime is 21422537. The reversal of 21422520 is 2522412.

21422520 is a `hidden beast` number, since 2 + 142 + 2 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21422493 and 21422502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1731 + ... + 6770.

It is an arithmetic number, because the mean of its divisors is an integer number (828945).

Almost surely, 2^21422520 is an apocalyptic number.

21422520 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 21422520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39789360).

21422520 is an abundant number, since it is smaller than the sum of its proper divisors (58156200).

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

21422520 is a wasteful number, since it uses less digits than its factorization.

21422520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8525 (or 8518 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 21422520 is about 4628.4468237196. The cubic root of 21422520 is about 277.7304635265.

Adding to 21422520 its reverse (2522412), we get a palindrome (23944932).

The spelling of 21422520 in words is "twenty-one million, four hundred twenty-two thousand, five hundred twenty".