20665019 has 2 divisors, whose sum is σ = 20665020. Its totient is φ = 20665018.

The previous prime is 20665009. The next prime is 20665033. The reversal of 20665019 is 91056602.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20665019 is a prime.

It is a super-2 number, since 2×20665019² = 854086020540722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20664982 and 20665000.

It is not a weakly prime, because it can be changed into another prime (20665009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332509 + 10332510.

It is an arithmetic number, because the mean of its divisors is an integer number (10332510).

Almost surely, 2^20665019 is an apocalyptic number.

20665019 is a deficient number, since it is larger than the sum of its proper divisors (1).

20665019 is an equidigital number, since it uses as much as digits as its factorization.

20665019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 20665019 is about 4545.8793428775. The cubic root of 20665019 is about 274.4175839143.

The spelling of 20665019 in words is "twenty million, six hundred sixty-five thousand, nineteen".