666126621667 has 12 divisors (see below), whose sum is σ = 752669961264. Its totient is φ = 588151930080.

The previous prime is 666126621653. The next prime is 666126621683. The reversal of 666126621667 is 766126621666.

It is not a de Polignac number, because 666126621667 - 2¹⁹ = 666126097379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666126621607) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85682584 + ... + 85690357.

It is an arithmetic number, because the mean of its divisors is an integer number (62722496772).

Almost surely, 2^666126621667 is an apocalyptic number.

666126621667 is a deficient number, since it is larger than the sum of its proper divisors (86543339597).

666126621667 is a wasteful number, since it uses less digits than its factorization.

666126621667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171372990 (or 171372977 counting only the distinct ones).

The product of its digits is 7838208, while the sum is 55.

Subtracting 666126621667 from its reverse (766126621666), we obtain a palindrome (99999999999).

The spelling of 666126621667 in words is "six hundred sixty-six billion, one hundred twenty-six million, six hundred twenty-one thousand, six hundred sixty-seven".