20791816 has 48 divisors (see below), whose sum is σ = 43299900. Its totient is φ = 9358976.

The previous prime is 20791801. The next prime is 20791819. The reversal of 20791816 is 61819702.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 20738916 + 52900 = 4554^2 + 230^2 .

It is a super-2 number, since 2×20791816² = 864599225155712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20791819) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 903981 + ... + 904003.

Almost surely, 2^20791816 is an apocalyptic number.

It is an amenable number.

20791816 is an abundant number, since it is smaller than the sum of its proper divisors (22508084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20791816 is an equidigital number, since it uses as much as digits as its factorization.

20791816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20791816 is about 4559.8043817690. The cubic root of 20791816 is about 274.9776995691.

Multiplying 20791816 by its sum of digits (34), we get a square (706921744 = 26588²).

20791816 divided by its sum of digits (34) gives a square (611524 = 782²).

The spelling of 20791816 in words is "twenty million, seven hundred ninety-one thousand, eight hundred sixteen".