21531056 has 10 divisors (see below), whose sum is σ = 41716452. Its totient is φ = 10765520.

The previous prime is 21531049. The next prime is 21531071. The reversal of 21531056 is 65013512.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672830 + ... + 672861.

Almost surely, 2^21531056 is an apocalyptic number.

It is an amenable number.

21531056 is a deficient number, since it is larger than the sum of its proper divisors (20185396).

21531056 is a wasteful number, since it uses less digits than its factorization.

21531056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1345699 (or 1345693 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 21531056 is about 4640.1568938992. The cubic root of 21531056 is about 278.1987089241.

Adding to 21531056 its reverse (65013512), we get a palindrome (86544568).

The spelling of 21531056 in words is "twenty-one million, five hundred thirty-one thousand, fifty-six".