20391236 has 12 divisors (see below), whose sum is σ = 36174012. Its totient is φ = 10055808.

The previous prime is 20391229. The next prime is 20391257. The reversal of 20391236 is 63219302.

It can be written as a sum of positive squares in 2 ways, for example, as 5522500 + 14868736 = 2350^2 + 3856^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34625 + ... + 35208.

It is an arithmetic number, because the mean of its divisors is an integer number (3014501).

Almost surely, 2^20391236 is an apocalyptic number.

It is an amenable number.

20391236 is a deficient number, since it is larger than the sum of its proper divisors (15782776).

20391236 is a wasteful number, since it uses less digits than its factorization.

20391236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69910 (or 69908 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 26.

The square root of 20391236 is about 4515.6656209246. The cubic root of 20391236 is about 273.2003074024.

The spelling of 20391236 in words is "twenty million, three hundred ninety-one thousand, two hundred thirty-six".