20697 has 4 divisors (see below), whose sum is σ = 27600. Its totient is φ = 13796.

The previous prime is 20693. The next prime is 20707. The reversal of 20697 is 79602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20697 - 2² = 20693 is a prime.

It is a D-number.

20697 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20697.

It is not an unprimeable number, because it can be changed into a prime (20693) 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 3 ways as a sum of consecutive naturals, for example, 3447 + ... + 3452.

It is an arithmetic number, because the mean of its divisors is an integer number (6900).

2²⁰⁶⁹⁷ is an apocalyptic number.

It is an amenable number.

20697 is a deficient number, since it is larger than the sum of its proper divisors (6903).

20697 is an equidigital number, since it uses as much as digits as its factorization.

20697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6902.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 20697 is about 143.8645196009. The cubic root of 20697 is about 27.4559073023.

It can be divided in two parts, 206 and 97, that added together give a palindrome (303).

The spelling of 20697 in words is "twenty thousand, six hundred ninety-seven".