66865511 has 2 divisors, whose sum is σ = 66865512. Its totient is φ = 66865510.

The previous prime is 66865507. The next prime is 66865553. The reversal of 66865511 is 11556866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66865511 - 2² = 66865507 is a prime.

It is a super-2 number, since 2×66865511² = 8941993122582242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66865411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33432755 + 33432756.

It is an arithmetic number, because the mean of its divisors is an integer number (33432756).

Almost surely, 2^66865511 is an apocalyptic number.

66865511 is a deficient number, since it is larger than the sum of its proper divisors (1).

66865511 is an equidigital number, since it uses as much as digits as its factorization.

66865511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 38.

The square root of 66865511 is about 8177.1334219273. The cubic root of 66865511 is about 405.8828700271.

It can be divided in two parts, 66865 and 511, that added together give a palindrome (67376).

The spelling of 66865511 in words is "sixty-six million, eight hundred sixty-five thousand, five hundred eleven".