135121999 has 2 divisors, whose sum is σ = 135122000. Its totient is φ = 135121998.

The previous prime is 135121993. The next prime is 135122041. The reversal of 135121999 is 999121531.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 135121999 - 2⁹ = 135121487 is a prime.

It is a super-2 number, since 2×135121999² = 36515909227512002, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135121993) 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, 67560999 + 67561000.

It is an arithmetic number, because the mean of its divisors is an integer number (67561000).

Almost surely, 2^135121999 is an apocalyptic number.

135121999 is a deficient number, since it is larger than the sum of its proper divisors (1).

135121999 is an equidigital number, since it uses as much as digits as its factorization.

135121999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21870, while the sum is 40.

The square root of 135121999 is about 11624.1988541146. The cubic root of 135121999 is about 513.1472673700.

The spelling of 135121999 in words is "one hundred thirty-five million, one hundred twenty-one thousand, nine hundred ninety-nine".