121559491 has 2 divisors, whose sum is σ = 121559492. Its totient is φ = 121559490.

The previous prime is 121559479. The next prime is 121559509. The reversal of 121559491 is 194955121.

It is a weak prime.

It is an emirp because it is prime and its reverse (194955121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121559491 - 2⁷ = 121559363 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121559491.

It is not a weakly prime, because it can be changed into another prime (121559791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60779745 + 60779746.

It is an arithmetic number, because the mean of its divisors is an integer number (60779746).

Almost surely, 2^121559491 is an apocalyptic number.

121559491 is a deficient number, since it is larger than the sum of its proper divisors (1).

121559491 is an equidigital number, since it uses as much as digits as its factorization.

121559491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 37.

The square root of 121559491 is about 11025.4020788359. The cubic root of 121559491 is about 495.3699115737.

It can be divided in two parts, 1215 and 59491, that added together give a palindrome (60706).

The spelling of 121559491 in words is "one hundred twenty-one million, five hundred fifty-nine thousand, four hundred ninety-one".