21732489 has 16 divisors (see below), whose sum is σ = 32381440. Its totient is φ = 14405040.

The previous prime is 21732481. The next prime is 21732497. The reversal of 21732489 is 98423712.

21732489 is a `hidden beast` number, since 2 + 173 + 2 + 489 = 666.

It is an interprime number because it is at equal distance from previous prime (21732481) and next prime (21732497).

It is not a de Polignac number, because 21732489 - 2³ = 21732481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21732481) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2664 + ... + 7110.

It is an arithmetic number, because the mean of its divisors is an integer number (2023840).

Almost surely, 2^21732489 is an apocalyptic number.

It is an amenable number.

21732489 is a deficient number, since it is larger than the sum of its proper divisors (10648951).

21732489 is a wasteful number, since it uses less digits than its factorization.

21732489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4637 (or 4631 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21732489 is about 4661.8117722619. The cubic root of 21732489 is about 279.0635766781.

The spelling of 21732489 in words is "twenty-one million, seven hundred thirty-two thousand, four hundred eighty-nine".