21485239 has 4 divisors (see below), whose sum is σ = 21787920. Its totient is φ = 21182560.

The previous prime is 21485231. The next prime is 21485249. The reversal of 21485239 is 93258412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21485239 - 2³ = 21485231 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 (21485231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151234 + ... + 151375.

It is an arithmetic number, because the mean of its divisors is an integer number (5446980).

Almost surely, 2^21485239 is an apocalyptic number.

21485239 is a deficient number, since it is larger than the sum of its proper divisors (302681).

21485239 is an equidigital number, since it uses as much as digits as its factorization.

21485239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302680.

The product of its digits is 17280, while the sum is 34.

The square root of 21485239 is about 4635.2172548868. The cubic root of 21485239 is about 278.0012378531.

The spelling of 21485239 in words is "twenty-one million, four hundred eighty-five thousand, two hundred thirty-nine".