21427432 has 16 divisors (see below), whose sum is σ = 43267140. Its totient is φ = 9889536.

The previous prime is 21427381. The next prime is 21427447. The reversal of 21427432 is 23472412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21399876 + 27556 = 4626^2 + 166^2 .

It is a super-2 number, since 2×21427432² = 918269684229248, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21427397 and 21427406.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102913 + ... + 103120.

Almost surely, 2^21427432 is an apocalyptic number.

It is an amenable number.

21427432 is an abundant number, since it is smaller than the sum of its proper divisors (21839708).

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

21427432 is a wasteful number, since it uses less digits than its factorization.

21427432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206052 (or 206048 counting only the distinct ones).

The product of its digits is 2688, while the sum is 25.

The square root of 21427432 is about 4628.9774248747. The cubic root of 21427432 is about 277.7516889750.

Adding to 21427432 its reverse (23472412), we get a palindrome (44899844).

The spelling of 21427432 in words is "twenty-one million, four hundred twenty-seven thousand, four hundred thirty-two".