123121291 has 4 divisors (see below), whose sum is σ = 123156712. Its totient is φ = 123085872.

The previous prime is 123121261. The next prime is 123121301. The reversal of 123121291 is 192121321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 192121321 = 7 ⋅27445903.

It is a cyclic number.

It is not a de Polignac number, because 123121291 - 2¹⁵ = 123088523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123121261) 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, 11850 + ... + 19663.

It is an arithmetic number, because the mean of its divisors is an integer number (30789178).

Almost surely, 2^123121291 is an apocalyptic number.

123121291 is a deficient number, since it is larger than the sum of its proper divisors (35421).

123121291 is an equidigital number, since it uses as much as digits as its factorization.

123121291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35420.

The product of its digits is 216, while the sum is 22.

The square root of 123121291 is about 11096.0033795957. The cubic root of 123121291 is about 497.4823993167.

It can be divided in two parts, 1231 and 21291, that added together give a palindrome (22522).

The spelling of 123121291 in words is "one hundred twenty-three million, one hundred twenty-one thousand, two hundred ninety-one".