18396820 has 48 divisors (see below), whose sum is σ = 41947920. Its totient is φ = 6736896.

The previous prime is 18396811. The next prime is 18396821. The reversal of 18396820 is 2869381.

It can be written as a sum of positive squares in 8 ways, for example, as 857476 + 17539344 = 926^2 + 4188^2 .

It is a super-2 number, since 2×18396820² = 676885972224800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 18396820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18396821) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 44776 + ... + 45184.

It is an arithmetic number, because the mean of its divisors is an integer number (873915).

Almost surely, 2^18396820 is an apocalyptic number.

18396820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18396820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20973960).

18396820 is an abundant number, since it is smaller than the sum of its proper divisors (23551100).

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

18396820 is a wasteful number, since it uses less digits than its factorization.

18396820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604 (or 602 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 18396820 is about 4289.1514312274. The cubic root of 18396820 is about 263.9860147168.

The spelling of 18396820 in words is "eighteen million, three hundred ninety-six thousand, eight hundred twenty".