121891831 has 2 divisors, whose sum is σ = 121891832. Its totient is φ = 121891830.

The previous prime is 121891829. The next prime is 121891837. The reversal of 121891831 is 138198121.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (138198121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121891831 - 2¹ = 121891829 is a prime.

It is a super-2 number, since 2×121891831² = 29715236929065122, which contains 22 as substring.

Together with 121891829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121891837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60945915 + 60945916.

It is an arithmetic number, because the mean of its divisors is an integer number (60945916).

Almost surely, 2^121891831 is an apocalyptic number.

121891831 is a deficient number, since it is larger than the sum of its proper divisors (1).

121891831 is an equidigital number, since it uses as much as digits as its factorization.

121891831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 34.

The square root of 121891831 is about 11040.4633507838. The cubic root of 121891831 is about 495.8209429445.

The spelling of 121891831 in words is "one hundred twenty-one million, eight hundred ninety-one thousand, eight hundred thirty-one".