122991 has 8 divisors (see below), whose sum is σ = 178944. Its totient is φ = 74520.

The previous prime is 122971. The next prime is 123001. The reversal of 122991 is 199221.

122991 = 64² + 65² + ... + 85².

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

It is not a de Polignac number, because 122991 - 2¹⁰ = 121967 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.

122991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (122921) 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, 1831 + ... + 1896.

It is an arithmetic number, because the mean of its divisors is an integer number (22368).

2¹²²⁹⁹¹ is an apocalyptic number.

122991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

122991 is a deficient number, since it is larger than the sum of its proper divisors (55953).

122991 is a wasteful number, since it uses less digits than its factorization.

122991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3741.

The product of its digits is 324, while the sum is 24.

The square root of 122991 is about 350.7007271164. The cubic root of 122991 is about 49.7306853300.

It can be divided in two parts, 12 and 2991, that added together give a palindrome (3003).

The spelling of 122991 in words is "one hundred twenty-two thousand, nine hundred ninety-one".