191690381665 has 8 divisors (see below), whose sum is σ = 231493608360. Its totient is φ = 152375538432.

The previous prime is 191690381629. The next prime is 191690381711. The reversal of 191690381665 is 566183096191.

It can be written as a sum of positive squares in 4 ways, for example, as 41679936 + 191648701729 = 6456^2 + 437777^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 191690381665 - 2⁷ = 191690381537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122095000 + ... + 122096569.

It is an arithmetic number, because the mean of its divisors is an integer number (28936701045).

Almost surely, 2^191690381665 is an apocalyptic number.

It is an amenable number.

191690381665 is a deficient number, since it is larger than the sum of its proper divisors (39803226695).

191690381665 is a wasteful number, since it uses less digits than its factorization.

191690381665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244191731.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 191690381665 in words is "one hundred ninety-one billion, six hundred ninety million, three hundred eighty-one thousand, six hundred sixty-five".