121388591 has 4 divisors (see below), whose sum is σ = 125304384. Its totient is φ = 117472800.

The previous prime is 121388569. The next prime is 121388593. The reversal of 121388591 is 195883121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121388591 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 (121388593) 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 in 3 ways as a sum of consecutive naturals, for example, 1957850 + ... + 1957911.

It is an arithmetic number, because the mean of its divisors is an integer number (31326096).

Almost surely, 2^121388591 is an apocalyptic number.

121388591 is a deficient number, since it is larger than the sum of its proper divisors (3915793).

121388591 is an equidigital number, since it uses as much as digits as its factorization.

121388591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3915792.

The product of its digits is 17280, while the sum is 38.

The square root of 121388591 is about 11017.6490686534. The cubic root of 121388591 is about 495.1376565081.

The spelling of 121388591 in words is "one hundred twenty-one million, three hundred eighty-eight thousand, five hundred ninety-one".