20997186 has 24 divisors (see below), whose sum is σ = 48851280. Its totient is φ = 5999112.

The previous prime is 20997181. The next prime is 20997187. The reversal of 20997186 is 68179902.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (20997181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35416 + ... + 36003.

It is an arithmetic number, because the mean of its divisors is an integer number (2035470).

Almost surely, 2^20997186 is an apocalyptic number.

20997186 is an abundant number, since it is smaller than the sum of its proper divisors (27854094).

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

20997186 is a wasteful number, since it uses less digits than its factorization.

20997186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71438 (or 71431 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 20997186 is about 4582.2686520980. The cubic root of 20997186 is about 275.8800938930.

The spelling of 20997186 in words is "twenty million, nine hundred ninety-seven thousand, one hundred eighty-six".