21579028 has 6 divisors (see below), whose sum is σ = 37763306. Its totient is φ = 10789512.

The previous prime is 21579023. The next prime is 21579031. The reversal of 21579028 is 82097512.

It can be written as a sum of positive squares in only one way, i.e., 20958084 + 620944 = 4578^2 + 788^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21578984 and 21579002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21579023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2697375 + ... + 2697382.

Almost surely, 2^21579028 is an apocalyptic number.

It is an amenable number.

21579028 is a deficient number, since it is larger than the sum of its proper divisors (16184278).

21579028 is a wasteful number, since it uses less digits than its factorization.

21579028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5394761 (or 5394759 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 21579028 is about 4645.3232395604. The cubic root of 21579028 is about 278.4051680516.

The spelling of 21579028 in words is "twenty-one million, five hundred seventy-nine thousand, twenty-eight".