20665229 has 4 divisors (see below), whose sum is σ = 22254876. Its totient is φ = 19075584.

The previous prime is 20665213. The next prime is 20665237. The reversal of 20665229 is 92256602.

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: 92256602 = 2 ⋅46128301.

It can be written as a sum of positive squares in 2 ways, for example, as 6901129 + 13764100 = 2627^2 + 3710^2 .

It is a cyclic number.

It is not a de Polignac number, because 20665229 - 2⁴ = 20665213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20665195 and 20665204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20665259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 794804 + ... + 794829.

It is an arithmetic number, because the mean of its divisors is an integer number (5563719).

Almost surely, 2^20665229 is an apocalyptic number.

It is an amenable number.

20665229 is a deficient number, since it is larger than the sum of its proper divisors (1589647).

20665229 is a wasteful number, since it uses less digits than its factorization.

20665229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1589646.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 20665229 is about 4545.9024406602. The cubic root of 20665229 is about 274.4185134641.

The spelling of 20665229 in words is "twenty million, six hundred sixty-five thousand, two hundred twenty-nine".