91724109 has 4 divisors (see below), whose sum is σ = 122298816. Its totient is φ = 61149404.

The previous prime is 91724107. The next prime is 91724131. The reversal of 91724109 is 90142719.

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: 90142719 = 3 ⋅30047573.

It is a cyclic number.

It is not a de Polignac number, because 91724109 - 2¹ = 91724107 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91724109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91724107) 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, 15287349 + ... + 15287354.

It is an arithmetic number, because the mean of its divisors is an integer number (30574704).

Almost surely, 2^91724109 is an apocalyptic number.

It is an amenable number.

91724109 is a deficient number, since it is larger than the sum of its proper divisors (30574707).

91724109 is a wasteful number, since it uses less digits than its factorization.

91724109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30574706.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 91724109 is about 9577.2704357766. The cubic root of 91724109 is about 450.9840342560.

The spelling of 91724109 in words is "ninety-one million, seven hundred twenty-four thousand, one hundred nine".