20390815 has 8 divisors (see below), whose sum is σ = 25038288. Its totient is φ = 15933120.

The previous prime is 20390767. The next prime is 20390827. The reversal of 20390815 is 51809302.

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

It is not a de Polignac number, because 20390815 - 2¹⁹ = 19866527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47206 + ... + 47635.

It is an arithmetic number, because the mean of its divisors is an integer number (3129786).

Almost surely, 2^20390815 is an apocalyptic number.

20390815 is a deficient number, since it is larger than the sum of its proper divisors (4647473).

20390815 is an equidigital number, since it uses as much as digits as its factorization.

20390815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94889.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 20390815 is about 4515.6190051863. The cubic root of 20390815 is about 273.1984272136.

The spelling of 20390815 in words is "twenty million, three hundred ninety thousand, eight hundred fifteen".