73117991 has 4 divisors (see below), whose sum is σ = 73148112. Its totient is φ = 73087872.

The previous prime is 73117981. The next prime is 73117997. The reversal of 73117991 is 19971137.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19971137 = 1009 ⋅19793.

It is a cyclic number.

It is not a de Polignac number, because 73117991 - 2⁶ = 73117927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73117997) 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, 11066 + ... + 16391.

It is an arithmetic number, because the mean of its divisors is an integer number (18287028).

Almost surely, 2^73117991 is an apocalyptic number.

73117991 is a deficient number, since it is larger than the sum of its proper divisors (30121).

73117991 is a wasteful number, since it uses less digits than its factorization.

73117991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30120.

The product of its digits is 11907, while the sum is 38.

The square root of 73117991 is about 8550.9058584456. The cubic root of 73117991 is about 418.1589693952.

The spelling of 73117991 in words is "seventy-three million, one hundred seventeen thousand, nine hundred ninety-one".