21900424 has 64 divisors (see below), whose sum is σ = 51408000. Its totient is φ = 8515584.

The previous prime is 21900421. The next prime is 21900427. The reversal of 21900424 is 42400912.

It is an interprime number because it is at equal distance from previous prime (21900421) and next prime (21900427).

It is a junction number, because it is equal to n+sod(n) for n = 21900395 and 21900404.

It is not an unprimeable number, because it can be changed into a prime (21900421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48552 + ... + 49000.

It is an arithmetic number, because the mean of its divisors is an integer number (803250).

Almost surely, 2^21900424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21900424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25704000).

21900424 is an abundant number, since it is smaller than the sum of its proper divisors (29507576).

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

21900424 is a wasteful number, since it uses less digits than its factorization.

21900424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21900424 is about 4679.7888841271. The cubic root of 21900424 is about 279.7805423247.

The spelling of 21900424 in words is "twenty-one million, nine hundred thousand, four hundred twenty-four".