75091391666 has 4 divisors (see below), whose sum is σ = 112637087502. Its totient is φ = 37545695832.

The previous prime is 75091391623. The next prime is 75091391677. The reversal of 75091391666 is 66619319057.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66619319057 = 42407 ⋅1570951.

It can be written as a sum of positive squares in only one way, i.e., 74630044225 + 461347441 = 273185^2 + 21479^2 .

It is a super-2 number, since 2×75091391666² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18772847915 + ... + 18772847918.

Almost surely, 2^75091391666 is an apocalyptic number.

75091391666 is a deficient number, since it is larger than the sum of its proper divisors (37545695836).

75091391666 is a wasteful number, since it uses less digits than its factorization.

75091391666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37545695835.

The product of its (nonzero) digits is 1837080, while the sum is 53.

The spelling of 75091391666 in words is "seventy-five billion, ninety-one million, three hundred ninety-one thousand, six hundred sixty-six".