135431921 has 2 divisors, whose sum is σ = 135431922. Its totient is φ = 135431920.

The previous prime is 135431917. The next prime is 135431953. The reversal of 135431921 is 129134531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125440000 + 9991921 = 11200^2 + 3161^2 .

It is an emirp because it is prime and its reverse (129134531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 135431921 - 2² = 135431917 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (135431971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67715960 + 67715961.

It is an arithmetic number, because the mean of its divisors is an integer number (67715961).

Almost surely, 2^135431921 is an apocalyptic number.

It is an amenable number.

135431921 is a deficient number, since it is larger than the sum of its proper divisors (1).

135431921 is an equidigital number, since it uses as much as digits as its factorization.

135431921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 29.

The square root of 135431921 is about 11637.5221159833. The cubic root of 135431921 is about 513.5392938172.

The spelling of 135431921 in words is "one hundred thirty-five million, four hundred thirty-one thousand, nine hundred twenty-one".