20782439 has 4 divisors (see below), whose sum is σ = 20800656. Its totient is φ = 20764224.

The previous prime is 20782417. The next prime is 20782469. The reversal of 20782439 is 93428702.

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 20782439 - 2²⁰ = 19733863 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20782399 and 20782408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20782469) 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, 7274 + ... + 9719.

It is an arithmetic number, because the mean of its divisors is an integer number (5200164).

Almost surely, 2^20782439 is an apocalyptic number.

20782439 is a deficient number, since it is larger than the sum of its proper divisors (18217).

20782439 is a wasteful number, since it uses less digits than its factorization.

20782439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18216.

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

The square root of 20782439 is about 4558.7760418779. The cubic root of 20782439 is about 274.9363555195.

The spelling of 20782439 in words is "twenty million, seven hundred eighty-two thousand, four hundred thirty-nine".