20215439 has 4 divisors (see below), whose sum is σ = 20226120. Its totient is φ = 20204760.

The previous prime is 20215417. The next prime is 20215451. The reversal of 20215439 is 93451202.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20215439 - 2²⁴ = 3438223 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 (20215739) 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, 1652 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (5056530).

Almost surely, 2^20215439 is an apocalyptic number.

20215439 is a deficient number, since it is larger than the sum of its proper divisors (10681).

20215439 is an equidigital number, since it uses as much as digits as its factorization.

20215439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10680.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20215439 is about 4496.1582489944. The cubic root of 20215439 is about 272.4129351795.

The spelling of 20215439 in words is "twenty million, two hundred fifteen thousand, four hundred thirty-nine".