666161700665 has 8 divisors (see below), whose sum is σ = 799398779400. Its totient is φ = 532926201472.

The previous prime is 666161700599. The next prime is 666161700667. The reversal of 666161700665 is 566007161666.

It can be written as a sum of positive squares in 4 ways, for example, as 44952904441 + 621208796224 = 212021^2 + 788168^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666161700665 - 2¹² = 666161696569 is a prime.

It is a super-2 number, since 2×666161700665² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666161700667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 948311 + ... + 1493859.

It is an arithmetic number, because the mean of its divisors is an integer number (99924847425).

Almost surely, 2^666161700665 is an apocalyptic number.

It is an amenable number.

666161700665 is a deficient number, since it is larger than the sum of its proper divisors (133237078735).

666161700665 is a wasteful number, since it uses less digits than its factorization.

666161700665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789771.

The product of its (nonzero) digits is 1632960, while the sum is 50.

The spelling of 666161700665 in words is "six hundred sixty-six billion, one hundred sixty-one million, seven hundred thousand, six hundred sixty-five".