121528991 has 2 divisors, whose sum is σ = 121528992. Its totient is φ = 121528990.

The previous prime is 121528969. The next prime is 121528999. The reversal of 121528991 is 199825121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121528991 - 2²² = 117334687 is a prime.

It is a Chen prime.

It is equal to p_6923738 and since 121528991 and 6923738 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121528999) 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, 60764495 + 60764496.

It is an arithmetic number, because the mean of its divisors is an integer number (60764496).

Almost surely, 2^121528991 is an apocalyptic number.

121528991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121528991 is an equidigital number, since it uses as much as digits as its factorization.

121528991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 38.

The square root of 121528991 is about 11024.0188225529. The cubic root of 121528991 is about 495.3284776882.

The spelling of 121528991 in words is "one hundred twenty-one million, five hundred twenty-eight thousand, nine hundred ninety-one".