21309232 has 20 divisors (see below), whose sum is σ = 47184976. Its totient is φ = 9132480.

The previous prime is 21309221. The next prime is 21309257. The reversal of 21309232 is 23290312.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95019 + ... + 95242.

Almost surely, 2^21309232 is an apocalyptic number.

It is an amenable number.

21309232 is an abundant number, since it is smaller than the sum of its proper divisors (25875744).

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

21309232 is a wasteful number, since it uses less digits than its factorization.

21309232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190276 (or 190270 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 21309232 is about 4616.1923703416. The cubic root of 21309232 is about 277.2400270640.

Adding to 21309232 its reverse (23290312), we get a palindrome (44599544).

The spelling of 21309232 in words is "twenty-one million, three hundred nine thousand, two hundred thirty-two".