20997575 has 6 divisors (see below), whose sum is σ = 26037024. Its totient is φ = 16798040.

The previous prime is 20997553. The next prime is 20997583. The reversal of 20997575 is 57579902.

It is not a de Polignac number, because 20997575 - 2⁶ = 20997511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 419927 + ... + 419976.

It is an arithmetic number, because the mean of its divisors is an integer number (4339504).

Almost surely, 2^20997575 is an apocalyptic number.

20997575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20997575 is a deficient number, since it is larger than the sum of its proper divisors (5039449).

20997575 is an equidigital number, since it uses as much as digits as its factorization.

20997575 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 839913 (or 839908 counting only the distinct ones).

The product of its (nonzero) digits is 198450, while the sum is 44.

The square root of 20997575 is about 4582.3110981250. The cubic root of 20997575 is about 275.8817975609.

The spelling of 20997575 in words is "twenty million, nine hundred ninety-seven thousand, five hundred seventy-five".