74391 has 8 divisors (see below), whose sum is σ = 100464. Its totient is φ = 48960.

The previous prime is 74383. The next prime is 74411. The reversal of 74391 is 19347.

74391 is nontrivially palindromic in base 12.

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

It is not a de Polignac number, because 74391 - 2³ = 74383 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

74391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (74311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 321 + ... + 501.

It is an arithmetic number, because the mean of its divisors is an integer number (12558).

2⁷⁴³⁹¹ is an apocalyptic number.

74391 is the 173-rd centered pentagonal number.

74391 is a deficient number, since it is larger than the sum of its proper divisors (26073).

74391 is a wasteful number, since it uses less digits than its factorization.

74391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321.

The product of its digits is 756, while the sum is 24.

The square root of 74391 is about 272.7471356403. The cubic root of 74391 is about 42.0571783585.

It can be divided in two parts, 74 and 391, that added together give a triangular number (465 = T₃₀).

The spelling of 74391 in words is "seventy-four thousand, three hundred ninety-one".