121111391 has 8 divisors (see below), whose sum is σ = 122325504. Its totient is φ = 119901600.

The previous prime is 121111379. The next prime is 121111409. The reversal of 121111391 is 193111121.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 121111391 - 2¹⁸ = 120849247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121114391) 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, 92441 + ... + 93741.

It is an arithmetic number, because the mean of its divisors is an integer number (15290688).

Almost surely, 2^121111391 is an apocalyptic number.

121111391 is a deficient number, since it is larger than the sum of its proper divisors (1214113).

121111391 is a wasteful number, since it uses less digits than its factorization.

121111391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2161.

The product of its digits is 54, while the sum is 20.

The square root of 121111391 is about 11005.0620625238. The cubic root of 121111391 is about 494.7604745307.

The spelling of 121111391 in words is "one hundred twenty-one million, one hundred eleven thousand, three hundred ninety-one".