20918873 has 4 divisors (see below), whose sum is σ = 20947920. Its totient is φ = 20889828.

The previous prime is 20918851. The next prime is 20918917. The reversal of 20918873 is 37881902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20918873 - 2¹⁰ = 20917849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20918813) 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, 13415 + ... + 14892.

It is an arithmetic number, because the mean of its divisors is an integer number (5236980).

Almost surely, 2^20918873 is an apocalyptic number.

It is an amenable number.

20918873 is a deficient number, since it is larger than the sum of its proper divisors (29047).

20918873 is an equidigital number, since it uses as much as digits as its factorization.

20918873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29046.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 20918873 is about 4573.7154480794. The cubic root of 20918873 is about 275.5366841686.

The spelling of 20918873 in words is "twenty million, nine hundred eighteen thousand, eight hundred seventy-three".