20731286 has 4 divisors (see below), whose sum is σ = 31096932. Its totient is φ = 10365642.

The previous prime is 20731283. The next prime is 20731301. The reversal of 20731286 is 68213702.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5182820 + ... + 5182823.

It is an arithmetic number, because the mean of its divisors is an integer number (7774233).

Almost surely, 2^20731286 is an apocalyptic number.

20731286 is a deficient number, since it is larger than the sum of its proper divisors (10365646).

20731286 is a wasteful number, since it uses less digits than its factorization.

20731286 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10365645.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 20731286 is about 4553.1621978577. The cubic root of 20731286 is about 274.7105980280.

Adding to 20731286 its reverse (68213702), we get a palindrome (88944988).

The spelling of 20731286 in words is "twenty million, seven hundred thirty-one thousand, two hundred eighty-six".