20689297 has 4 divisors (see below), whose sum is σ = 21193956. Its totient is φ = 20184640.

The previous prime is 20689247. The next prime is 20689313. The reversal of 20689297 is 79298602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79298602 = 2 ⋅39649301.

It can be written as a sum of positive squares in 2 ways, for example, as 11350161 + 9339136 = 3369^2 + 3056^2 .

It is a cyclic number.

It is not a de Polignac number, because 20689297 - 2¹⁵ = 20656529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20689217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 252268 + ... + 252349.

It is an arithmetic number, because the mean of its divisors is an integer number (5298489).

Almost surely, 2^20689297 is an apocalyptic number.

It is an amenable number.

20689297 is a deficient number, since it is larger than the sum of its proper divisors (504659).

20689297 is an equidigital number, since it uses as much as digits as its factorization.

20689297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504658.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 20689297 is about 4548.5488894811. The cubic root of 20689297 is about 274.5250070394.

The spelling of 20689297 in words is "twenty million, six hundred eighty-nine thousand, two hundred ninety-seven".