121664591 has 2 divisors, whose sum is σ = 121664592. Its totient is φ = 121664590.

The previous prime is 121664579. The next prime is 121664633. The reversal of 121664591 is 195466121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121664591 - 2¹⁸ = 121402447 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121664531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60832295 + 60832296.

It is an arithmetic number, because the mean of its divisors is an integer number (60832296).

Almost surely, 2^121664591 is an apocalyptic number.

121664591 is a deficient number, since it is larger than the sum of its proper divisors (1).

121664591 is an equidigital number, since it uses as much as digits as its factorization.

121664591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 35.

The square root of 121664591 is about 11030.1673151408. The cubic root of 121664591 is about 495.5126356009.

The spelling of 121664591 in words is "one hundred twenty-one million, six hundred sixty-four thousand, five hundred ninety-one".