91687641 has 4 divisors (see below), whose sum is σ = 122250192. Its totient is φ = 61125092.

The previous prime is 91687627. The next prime is 91687649. The reversal of 91687641 is 14678619.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 14678619 = 3 ⋅4892873.

It is a cyclic number.

It is not a de Polignac number, because 91687641 - 2⁹ = 91687129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 91687593 and 91687602.

It is not an unprimeable number, because it can be changed into a prime (91687649) 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, 15281271 + ... + 15281276.

It is an arithmetic number, because the mean of its divisors is an integer number (30562548).

Almost surely, 2^91687641 is an apocalyptic number.

It is an amenable number.

91687641 is a deficient number, since it is larger than the sum of its proper divisors (30562551).

91687641 is a wasteful number, since it uses less digits than its factorization.

91687641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30562550.

The product of its digits is 72576, while the sum is 42.

The square root of 91687641 is about 9575.3663637482. The cubic root of 91687641 is about 450.9242583838.

The spelling of 91687641 in words is "ninety-one million, six hundred eighty-seven thousand, six hundred forty-one".