123191391 has 32 divisors (see below), whose sum is σ = 174988800. Its totient is φ = 76970880.

The previous prime is 123191353. The next prime is 123191407. The reversal of 123191391 is 193191321.

It is a happy number.

It is not a de Polignac number, because 123191391 - 2¹⁴ = 123175007 is a prime.

It is a super-2 number, since 2×123191391² = 30352237633029762, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123191191) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 737590 + ... + 737756.

It is an arithmetic number, because the mean of its divisors is an integer number (5468400).

Almost surely, 2^123191391 is an apocalyptic number.

123191391 is a deficient number, since it is larger than the sum of its proper divisors (51797409).

123191391 is a wasteful number, since it uses less digits than its factorization.

123191391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399.

The product of its digits is 1458, while the sum is 30.

The square root of 123191391 is about 11099.1617251034. The cubic root of 123191391 is about 497.5767964745.

The spelling of 123191391 in words is "one hundred twenty-three million, one hundred ninety-one thousand, three hundred ninety-one".