20693909 has 2 divisors, whose sum is σ = 20693910. Its totient is φ = 20693908.

The previous prime is 20693891. The next prime is 20693917. The reversal of 20693909 is 90939602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18037009 + 2656900 = 4247^2 + 1630^2 .

It is a cyclic number.

It is not a de Polignac number, because 20693909 - 2¹² = 20689813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20693929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10346954 + 10346955.

It is an arithmetic number, because the mean of its divisors is an integer number (10346955).

Almost surely, 2^20693909 is an apocalyptic number.

It is an amenable number.

20693909 is a deficient number, since it is larger than the sum of its proper divisors (1).

20693909 is an equidigital number, since it uses as much as digits as its factorization.

20693909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26244, while the sum is 38.

The square root of 20693909 is about 4549.0558361049. The cubic root of 20693909 is about 274.5454043051.

The spelling of 20693909 in words is "twenty million, six hundred ninety-three thousand, nine hundred nine".