121538551 has 2 divisors, whose sum is σ = 121538552. Its totient is φ = 121538550.

The previous prime is 121538531. The next prime is 121538563. The reversal of 121538551 is 155835121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121538551 - 2⁵ = 121538519 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 (121538531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60769275 + 60769276.

It is an arithmetic number, because the mean of its divisors is an integer number (60769276).

Almost surely, 2^121538551 is an apocalyptic number.

121538551 is a deficient number, since it is larger than the sum of its proper divisors (1).

121538551 is an equidigital number, since it uses as much as digits as its factorization.

121538551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6000, while the sum is 31.

The square root of 121538551 is about 11024.4524127051. The cubic root of 121538551 is about 495.3414655798.

The spelling of 121538551 in words is "one hundred twenty-one million, five hundred thirty-eight thousand, five hundred fifty-one".