21807432 has 48 divisors (see below), whose sum is σ = 59514000. Its totient is φ = 7213536.

The previous prime is 21807431. The next prime is 21807463. The reversal of 21807432 is 23470812.

It is a junction number, because it is equal to n+sod(n) for n = 21807396 and 21807405.

It is not an unprimeable number, because it can be changed into a prime (21807431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8919 + ... + 11097.

It is an arithmetic number, because the mean of its divisors is an integer number (1239875).

Almost surely, 2^21807432 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21807432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29757000).

21807432 is an abundant number, since it is smaller than the sum of its proper divisors (37706568).

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

21807432 is a wasteful number, since it uses less digits than its factorization.

21807432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2330 (or 2323 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21807432 is about 4669.8428239075. The cubic root of 21807432 is about 279.3839858678.

The spelling of 21807432 in words is "twenty-one million, eight hundred seven thousand, four hundred thirty-two".