7191566666 has 4 divisors (see below), whose sum is σ = 10787350002. Its totient is φ = 3595783332.

The previous prime is 7191566617. The next prime is 7191566689. The reversal of 7191566666 is 6666651917.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6666651917 = 521 ⋅12795877.

It can be written as a sum of positive squares in only one way, i.e., 7101601441 + 89965225 = 84271^2 + 9485^2 .

It is a super-2 number, since 2×7191566666² (a number of 21 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, 1797891665 + ... + 1797891668.

Almost surely, 2^7191566666 is an apocalyptic number.

7191566666 is a deficient number, since it is larger than the sum of its proper divisors (3595783336).

7191566666 is a wasteful number, since it uses less digits than its factorization.

7191566666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3595783335.

The product of its digits is 2449440, while the sum is 53.

The square root of 7191566666 is about 84803.1052851250. The cubic root of 7191566666 is about 1930.2245585133.

The spelling of 7191566666 in words is "seven billion, one hundred ninety-one million, five hundred sixty-six thousand, six hundred sixty-six".