91661111678 has 8 divisors (see below), whose sum is σ = 137497968840. Its totient is φ = 45828455400.

The previous prime is 91661111671. The next prime is 91661111713. The reversal of 91661111678 is 87611116619.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91661111671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 995093 + ... + 1083296.

It is an arithmetic number, because the mean of its divisors is an integer number (17187246105).

Almost surely, 2^91661111678 is an apocalyptic number.

91661111678 is a deficient number, since it is larger than the sum of its proper divisors (45836857162).

91661111678 is a wasteful number, since it uses less digits than its factorization.

91661111678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100442.

The product of its digits is 108864, while the sum is 47.

The spelling of 91661111678 in words is "ninety-one billion, six hundred sixty-one million, one hundred eleven thousand, six hundred seventy-eight".