20724136 has 16 divisors (see below), whose sum is σ = 40903200. Its totient is φ = 9816624.

The previous prime is 20724097. The next prime is 20724161. The reversal of 20724136 is 63142702.

It is a self number, because there is not a number n which added to its sum of digits gives 20724136.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68020 + ... + 68323.

It is an arithmetic number, because the mean of its divisors is an integer number (2556450).

Almost surely, 2^20724136 is an apocalyptic number.

It is an amenable number.

20724136 is a deficient number, since it is larger than the sum of its proper divisors (20179064).

20724136 is a wasteful number, since it uses less digits than its factorization.

20724136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136368 (or 136364 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 20724136 is about 4552.3769615444. The cubic root of 20724136 is about 274.6790128090.

Adding to 20724136 its reverse (63142702), we get a palindrome (83866838).

The spelling of 20724136 in words is "twenty million, seven hundred twenty-four thousand, one hundred thirty-six".