665666151605 has 16 divisors (see below), whose sum is σ = 983137701504. Its totient is φ = 421344728640.

The previous prime is 665666151581. The next prime is 665666151617. The reversal of 665666151605 is 506151666566.

It is a happy number.

It is not a de Polignac number, because 665666151605 - 2²⁰ = 665665103029 is a prime.

It is a super-2 number, since 2×665666151605² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 731500811 + ... + 731501720.

It is an arithmetic number, because the mean of its divisors is an integer number (61446106344).

Almost surely, 2^665666151605 is an apocalyptic number.

665666151605 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

665666151605 is a deficient number, since it is larger than the sum of its proper divisors (317471549899).

665666151605 is a wasteful number, since it uses less digits than its factorization.

665666151605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1463002556.

The product of its (nonzero) digits is 5832000, while the sum is 53.

The spelling of 665666151605 in words is "six hundred sixty-five billion, six hundred sixty-six million, one hundred fifty-one thousand, six hundred five".