21553432 has 32 divisors (see below), whose sum is σ = 42007680. Its totient is φ = 10356480.

The previous prime is 21553421. The next prime is 21553453. The reversal of 21553432 is 23435512.

It is a junction number, because it is equal to n+sod(n) for n = 21553397 and 21553406.

It is a congruent number.

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, 57598 + ... + 57970.

It is an arithmetic number, because the mean of its divisors is an integer number (1312740).

Almost surely, 2^21553432 is an apocalyptic number.

It is an amenable number.

21553432 is a deficient number, since it is larger than the sum of its proper divisors (20454248).

21553432 is a wasteful number, since it uses less digits than its factorization.

21553432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643 (or 639 counting only the distinct ones).

The product of its digits is 3600, while the sum is 25.

The square root of 21553432 is about 4642.5673931565. The cubic root of 21553432 is about 278.2950475823.

Adding to 21553432 its reverse (23435512), we get a palindrome (44988944).

The spelling of 21553432 in words is "twenty-one million, five hundred fifty-three thousand, four hundred thirty-two".