121791491 has 2 divisors, whose sum is σ = 121791492. Its totient is φ = 121791490.

The previous prime is 121791487. The next prime is 121791497. The reversal of 121791491 is 194197121.

It is a weak prime.

It is an emirp because it is prime and its reverse (194197121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121791491 - 2² = 121791487 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (121791497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60895745 + 60895746.

It is an arithmetic number, because the mean of its divisors is an integer number (60895746).

Almost surely, 2^121791491 is an apocalyptic number.

121791491 is a deficient number, since it is larger than the sum of its proper divisors (1).

121791491 is an equidigital number, since it uses as much as digits as its factorization.

121791491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 35.

The square root of 121791491 is about 11035.9182218790. The cubic root of 121791491 is about 495.6848541663.

The spelling of 121791491 in words is "one hundred twenty-one million, seven hundred ninety-one thousand, four hundred ninety-one".