20872439 has 4 divisors (see below), whose sum is σ = 23854224. Its totient is φ = 17890656.

The previous prime is 20872433. The next prime is 20872457. The reversal of 20872439 is 93427802.

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

It is not a de Polignac number, because 20872439 - 2¹² = 20868343 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20872399 and 20872408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20872433) 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, 1490882 + ... + 1490895.

It is an arithmetic number, because the mean of its divisors is an integer number (5963556).

Almost surely, 2^20872439 is an apocalyptic number.

20872439 is a deficient number, since it is larger than the sum of its proper divisors (2981785).

20872439 is an equidigital number, since it uses as much as digits as its factorization.

20872439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2981784.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 20872439 is about 4568.6364486573. The cubic root of 20872439 is about 275.3326618863.

The spelling of 20872439 in words is "twenty million, eight hundred seventy-two thousand, four hundred thirty-nine".