121557889 has 2 divisors, whose sum is σ = 121557890. Its totient is φ = 121557888.

The previous prime is 121557857. The next prime is 121557911. The reversal of 121557889 is 988755121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 91527489 + 30030400 = 9567^2 + 5480^2 .

It is a cyclic number.

It is not a de Polignac number, because 121557889 - 2⁵ = 121557857 is a prime.

It is not a weakly prime, because it can be changed into another prime (121557809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60778944 + 60778945.

It is an arithmetic number, because the mean of its divisors is an integer number (60778945).

Almost surely, 2^121557889 is an apocalyptic number.

It is an amenable number.

121557889 is a deficient number, since it is larger than the sum of its proper divisors (1).

121557889 is an equidigital number, since it uses as much as digits as its factorization.

121557889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 46.

The square root of 121557889 is about 11025.3294281849. The cubic root of 121557889 is about 495.3677354483.

The spelling of 121557889 in words is "one hundred twenty-one million, five hundred fifty-seven thousand, eight hundred eighty-nine".