21389732 has 24 divisors (see below), whose sum is σ = 46070976. Its totient is φ = 8461728.

The previous prime is 21389729. The next prime is 21389743. The reversal of 21389732 is 23798312.

It is a junction number, because it is equal to n+sod(n) for n = 21389692 and 21389701.

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, 29018 + ... + 29745.

It is an arithmetic number, because the mean of its divisors is an integer number (1919624).

Almost surely, 2^21389732 is an apocalyptic number.

It is an amenable number.

21389732 is an abundant number, since it is smaller than the sum of its proper divisors (24681244).

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

21389732 is a wasteful number, since it uses less digits than its factorization.

21389732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58787 (or 58785 counting only the distinct ones).

The product of its digits is 18144, while the sum is 35.

The square root of 21389732 is about 4624.9034584519. The cubic root of 21389732 is about 277.5886987512.

The spelling of 21389732 in words is "twenty-one million, three hundred eighty-nine thousand, seven hundred thirty-two".