20660399 has 2 divisors, whose sum is σ = 20660400. Its totient is φ = 20660398.

The previous prime is 20660377. The next prime is 20660473. The reversal of 20660399 is 99306602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20660399 - 2¹² = 20656303 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20660329) 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 as a sum of consecutive naturals, namely, 10330199 + 10330200.

It is an arithmetic number, because the mean of its divisors is an integer number (10330200).

Almost surely, 2^20660399 is an apocalyptic number.

20660399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20660399 is an equidigital number, since it uses as much as digits as its factorization.

20660399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 35.

The square root of 20660399 is about 4545.3711619625. The cubic root of 20660399 is about 274.3971322236.

The spelling of 20660399 in words is "twenty million, six hundred sixty thousand, three hundred ninety-nine".