20391836 has 6 divisors (see below), whose sum is σ = 35685720. Its totient is φ = 10195916.

The previous prime is 20391821. The next prime is 20391841. The reversal of 20391836 is 63819302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2548976 + ... + 2548983.

It is an arithmetic number, because the mean of its divisors is an integer number (5947620).

Almost surely, 2^20391836 is an apocalyptic number.

It is an amenable number.

20391836 is a deficient number, since it is larger than the sum of its proper divisors (15293884).

20391836 is a wasteful number, since it uses less digits than its factorization.

20391836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5097963 (or 5097961 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 20391836 is about 4515.7320558244. The cubic root of 20391836 is about 273.2029869617.

The spelling of 20391836 in words is "twenty million, three hundred ninety-one thousand, eight hundred thirty-six".