45991 has 8 divisors (see below), whose sum is σ = 51984. Its totient is φ = 40320.

The previous prime is 45989. The next prime is 46021. The reversal of 45991 is 19954.

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

It is a 7-Lehmer number, since φ(45991) divides (45991-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 45991 - 2¹ = 45989 is a prime.

It is a Duffinian number.

45991 is a lucky number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (45971) 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, 351 + ... + 463.

It is an arithmetic number, because the mean of its divisors is an integer number (6498).

2⁴⁵⁹⁹¹ is an apocalyptic number.

45991 is a deficient number, since it is larger than the sum of its proper divisors (5993).

45991 is a wasteful number, since it uses less digits than its factorization.

45991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161.

The product of its digits is 1620, while the sum is 28.

The square root of 45991 is about 214.4551235107. The cubic root of 45991 is about 35.8281417874.

It can be divided in two parts, 4 and 5991, that added together give a palindrome (5995).

The spelling of 45991 in words is "forty-five thousand, nine hundred ninety-one".