20503865 has 8 divisors (see below), whose sum is σ = 25398528. Its totient is φ = 15873840.

The previous prime is 20503843. The next prime is 20503867. The reversal of 20503865 is 56830502.

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

It is not a de Polignac number, because 20503865 - 2¹⁸ = 20241721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20503867) 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, 65987 + ... + 66296.

It is an arithmetic number, because the mean of its divisors is an integer number (3174816).

Almost surely, 2^20503865 is an apocalyptic number.

It is an amenable number.

20503865 is a deficient number, since it is larger than the sum of its proper divisors (4894663).

20503865 is a wasteful number, since it uses less digits than its factorization.

20503865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132319.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 20503865 is about 4528.1193668012. The cubic root of 20503865 is about 273.7023825491.

The spelling of 20503865 in words is "twenty million, five hundred three thousand, eight hundred sixty-five".