91640679 has 16 divisors (see below), whose sum is σ = 131843712. Its totient is φ = 56284128.

The previous prime is 91640677. The next prime is 91640683. The reversal of 91640679 is 97604619.

It is not a de Polignac number, because 91640679 - 2¹ = 91640677 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91640679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91640677) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20892 + ... + 24894.

It is an arithmetic number, because the mean of its divisors is an integer number (8240232).

Almost surely, 2^91640679 is an apocalyptic number.

91640679 is a deficient number, since it is larger than the sum of its proper divisors (40203033).

91640679 is a wasteful number, since it uses less digits than its factorization.

91640679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4606.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 91640679 is about 9572.9138197312. The cubic root of 91640679 is about 450.8472581058.

The spelling of 91640679 in words is "ninety-one million, six hundred forty thousand, six hundred seventy-nine".