20904393 has 8 divisors (see below), whose sum is σ = 28050688. Its totient is φ = 13847184.

The previous prime is 20904391. The next prime is 20904397. The reversal of 20904393 is 39340902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20904393 - 2¹ = 20904391 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20904393.

It is not an unprimeable number, because it can be changed into a prime (20904391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21721 + ... + 22662.

It is an arithmetic number, because the mean of its divisors is an integer number (3506336).

Almost surely, 2^20904393 is an apocalyptic number.

It is an amenable number.

20904393 is a deficient number, since it is larger than the sum of its proper divisors (7146295).

20904393 is a wasteful number, since it uses less digits than its factorization.

20904393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44543.

The product of its (nonzero) digits is 5832, while the sum is 30.

The square root of 20904393 is about 4572.1322159360. The cubic root of 20904393 is about 275.4730941892.

The spelling of 20904393 in words is "twenty million, nine hundred four thousand, three hundred ninety-three".