21242732 has 24 divisors (see below), whose sum is σ = 43952160. Its totient is φ = 8789760.

The previous prime is 21242729. The next prime is 21242747. The reversal of 21242732 is 23724212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21242698 and 21242707.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12269 + ... + 13892.

It is an arithmetic number, because the mean of its divisors is an integer number (1831340).

Almost surely, 2^21242732 is an apocalyptic number.

It is an amenable number.

21242732 is an abundant number, since it is smaller than the sum of its proper divisors (22709428).

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

21242732 is a wasteful number, since it uses less digits than its factorization.

21242732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26201 (or 26199 counting only the distinct ones).

The product of its digits is 1344, while the sum is 23.

The square root of 21242732 is about 4608.9838359448. The cubic root of 21242732 is about 276.9513310124.

Adding to 21242732 its reverse (23724212), we get a palindrome (44966944).

The spelling of 21242732 in words is "twenty-one million, two hundred forty-two thousand, seven hundred thirty-two".