20997499 has 8 divisors (see below), whose sum is σ = 22302000. Its totient is φ = 19700736.

The previous prime is 20997491. The next prime is 20997511. The reversal of 20997499 is 99479902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20997499 - 2³ = 20997491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20997491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4252 + ... + 7750.

It is an arithmetic number, because the mean of its divisors is an integer number (2787750).

Almost surely, 2^20997499 is an apocalyptic number.

20997499 is a deficient number, since it is larger than the sum of its proper divisors (1304501).

20997499 is a wasteful number, since it uses less digits than its factorization.

20997499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3869.

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 20997499 is about 4582.3028053589. The cubic root of 20997499 is about 275.8814647122.

The spelling of 20997499 in words is "twenty million, nine hundred ninety-seven thousand, four hundred ninety-nine".