666264120417661 has 4 divisors (see below), whose sum is σ = 670253725929312. Its totient is φ = 662274514906012.

The previous prime is 666264120417569. The next prime is 666264120417743. The reversal of 666264120417661 is 166714021462666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 666264120417661 - 2²³ = 666264112029053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666264120417596 and 666264120417605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666264120417761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1994802755575 + ... + 1994802755908.

It is an arithmetic number, because the mean of its divisors is an integer number (167563431482328).

Almost surely, 2^{666264120417661} is an apocalyptic number.

It is an amenable number.

666264120417661 is a deficient number, since it is larger than the sum of its proper divisors (3989605511651).

666264120417661 is a wasteful number, since it uses less digits than its factorization.

666264120417661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3989605511650.

The product of its (nonzero) digits is 20901888, while the sum is 58.

The spelling of 666264120417661 in words is "six hundred sixty-six trillion, two hundred sixty-four billion, one hundred twenty million, four hundred seventeen thousand, six hundred sixty-one".