66190865 has 16 divisors (see below), whose sum is σ = 86174928. Its totient is φ = 48516096.

The previous prime is 66190823. The next prime is 66190867. The reversal of 66190865 is 56809166.

It can be written as a sum of positive squares in 8 ways, for example, as 14753281 + 51437584 = 3841^2 + 7172^2 .

It is a cyclic number.

It is not a de Polignac number, because 66190865 - 2⁸ = 66190609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66190867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5189 + ... + 12621.

It is an arithmetic number, because the mean of its divisors is an integer number (5385933).

Almost surely, 2^66190865 is an apocalyptic number.

66190865 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66190865 is a deficient number, since it is larger than the sum of its proper divisors (19984063).

66190865 is a wasteful number, since it uses less digits than its factorization.

66190865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7588.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 66190865 is about 8135.7768528887. The cubic root of 66190865 is about 404.5131883919.

The spelling of 66190865 in words is "sixty-six million, one hundred ninety thousand, eight hundred sixty-five".