666638091519 has 4 divisors (see below), whose sum is σ = 888850788696. Its totient is φ = 444425394344.

The previous prime is 666638091463. The next prime is 666638091563. The reversal of 666638091519 is 915190836666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666638091519 - 2²⁰ = 666637042943 is a prime.

It is a super-2 number, since 2×666638091519² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666638091719) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 111106348584 + ... + 111106348589.

It is an arithmetic number, because the mean of its divisors is an integer number (222212697174).

Almost surely, 2^666638091519 is an apocalyptic number.

666638091519 is a deficient number, since it is larger than the sum of its proper divisors (222212697177).

666638091519 is a wasteful number, since it uses less digits than its factorization.

666638091519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222212697176.

The product of its (nonzero) digits is 12597120, while the sum is 60.

The spelling of 666638091519 in words is "six hundred sixty-six billion, six hundred thirty-eight million, ninety-one thousand, five hundred nineteen".