20784479 has 4 divisors (see below), whose sum is σ = 21688176. Its totient is φ = 19880784.

The previous prime is 20784451. The next prime is 20784493. The reversal of 20784479 is 97448702.

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 20784479 - 2⁸ = 20784223 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 (20784409) 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, 451814 + ... + 451859.

It is an arithmetic number, because the mean of its divisors is an integer number (5422044).

Almost surely, 2^20784479 is an apocalyptic number.

20784479 is a deficient number, since it is larger than the sum of its proper divisors (903697).

20784479 is an equidigital number, since it uses as much as digits as its factorization.

20784479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903696.

The product of its (nonzero) digits is 112896, while the sum is 41.

The square root of 20784479 is about 4558.9997806536. Note that the first 3 decimals coincide. The cubic root of 20784479 is about 274.9453511242.

The spelling of 20784479 in words is "twenty million, seven hundred eighty-four thousand, four hundred seventy-nine".