21583428 has 12 divisors (see below), whose sum is σ = 50361360. Its totient is φ = 7194472.

The previous prime is 21583427. The next prime is 21583433. The reversal of 21583428 is 82438512.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21583423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 899298 + ... + 899321.

It is an arithmetic number, because the mean of its divisors is an integer number (4196780).

Almost surely, 2^21583428 is an apocalyptic number.

It is an amenable number.

21583428 is an abundant number, since it is smaller than the sum of its proper divisors (28777932).

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

21583428 is a wasteful number, since it uses less digits than its factorization.

21583428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798626 (or 1798624 counting only the distinct ones).

The product of its digits is 15360, while the sum is 33.

The square root of 21583428 is about 4645.7968100209. The cubic root of 21583428 is about 278.4240891925.

The spelling of 21583428 in words is "twenty-one million, five hundred eighty-three thousand, four hundred twenty-eight".