21529989 has 16 divisors (see below), whose sum is σ = 34350400. Its totient is φ = 13249008.

The previous prime is 21529979. The next prime is 21529997. The reversal of 21529989 is 98992512.

It is not a de Polignac number, because 21529989 - 2⁵ = 21529957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21529979) 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, 30319 + ... + 31020.

It is an arithmetic number, because the mean of its divisors is an integer number (2146900).

Almost surely, 2^21529989 is an apocalyptic number.

It is an amenable number.

21529989 is a deficient number, since it is larger than the sum of its proper divisors (12820411).

21529989 is a wasteful number, since it uses less digits than its factorization.

21529989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61361 (or 61355 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The square root of 21529989 is about 4640.0419179141. The cubic root of 21529989 is about 278.1941133463.

The spelling of 21529989 in words is "twenty-one million, five hundred twenty-nine thousand, nine hundred eighty-nine".