20665837 has 2 divisors, whose sum is σ = 20665838. Its totient is φ = 20665836.

The previous prime is 20665819. The next prime is 20665849. The reversal of 20665837 is 73856602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17089956 + 3575881 = 4134^2 + 1891^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20665837 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20665796 and 20665805.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20665807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332918 + 10332919.

It is an arithmetic number, because the mean of its divisors is an integer number (10332919).

Almost surely, 2^20665837 is an apocalyptic number.

It is an amenable number.

20665837 is a deficient number, since it is larger than the sum of its proper divisors (1).

20665837 is an equidigital number, since it uses as much as digits as its factorization.

20665837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 37.

The square root of 20665837 is about 4545.9693135788. The cubic root of 20665837 is about 274.4212046968.

The spelling of 20665837 in words is "twenty million, six hundred sixty-five thousand, eight hundred thirty-seven".