20718836 has 6 divisors (see below), whose sum is σ = 36257970. Its totient is φ = 10359416.

The previous prime is 20718823. The next prime is 20718839. The reversal of 20718836 is 63881702.

It can be written as a sum of positive squares in only one way, i.e., 17808400 + 2910436 = 4220^2 + 1706^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20718796 and 20718805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20718839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2589851 + ... + 2589858.

It is an arithmetic number, because the mean of its divisors is an integer number (6042995).

Almost surely, 2^20718836 is an apocalyptic number.

It is an amenable number.

20718836 is a deficient number, since it is larger than the sum of its proper divisors (15539134).

20718836 is a wasteful number, since it uses less digits than its factorization.

20718836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5179713 (or 5179711 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 20718836 is about 4551.7948108411. The cubic root of 20718836 is about 274.6555953005.

The spelling of 20718836 in words is "twenty million, seven hundred eighteen thousand, eight hundred thirty-six".