21887432 has 64 divisors (see below), whose sum is σ = 50440320. Its totient is φ = 8690688.

The previous prime is 21887429. The next prime is 21887447. The reversal of 21887432 is 23478812.

It is a junction number, because it is equal to n+sod(n) for n = 21887392 and 21887401.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78878 + ... + 79154.

It is an arithmetic number, because the mean of its divisors is an integer number (788130).

Almost surely, 2^21887432 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 21887432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25220160).

21887432 is an abundant number, since it is smaller than the sum of its proper divisors (28552888).

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

21887432 is a wasteful number, since it uses less digits than its factorization.

21887432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390 (or 386 counting only the distinct ones).

The product of its digits is 21504, while the sum is 35.

The square root of 21887432 is about 4678.4005813953. The cubic root of 21887432 is about 279.7252065951.

The spelling of 21887432 in words is "twenty-one million, eight hundred eighty-seven thousand, four hundred thirty-two".