20997513 has 12 divisors (see below), whose sum is σ = 30401280. Its totient is φ = 13965336.

The previous prime is 20997511. The next prime is 20997517. The reversal of 20997513 is 31579902.

It is not a de Polignac number, because 20997513 - 2¹ = 20997511 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20997511) 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, 1648 + ... + 6686.

It is an arithmetic number, because the mean of its divisors is an integer number (2533440).

Almost surely, 2^20997513 is an apocalyptic number.

It is an amenable number.

20997513 is a deficient number, since it is larger than the sum of its proper divisors (9403767).

20997513 is a wasteful number, since it uses less digits than its factorization.

20997513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5508 (or 5505 counting only the distinct ones).

The product of its (nonzero) digits is 17010, while the sum is 36.

The square root of 20997513 is about 4582.3043329748. The cubic root of 20997513 is about 275.8815260265.

The spelling of 20997513 in words is "twenty million, nine hundred ninety-seven thousand, five hundred thirteen".