135131921 has 2 divisors, whose sum is σ = 135131922. Its totient is φ = 135131920.

The previous prime is 135131911. The next prime is 135131951. The reversal of 135131921 is 129131531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 88360000 + 46771921 = 9400^2 + 6839^2 .

It is an emirp because it is prime and its reverse (129131531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 135131921 - 2¹⁴ = 135115537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (135131911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67565960 + 67565961.

It is an arithmetic number, because the mean of its divisors is an integer number (67565961).

Almost surely, 2^135131921 is an apocalyptic number.

It is an amenable number.

135131921 is a deficient number, since it is larger than the sum of its proper divisors (1).

135131921 is an equidigital number, since it uses as much as digits as its factorization.

135131921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 26.

The square root of 135131921 is about 11624.6256283805. The cubic root of 135131921 is about 513.1598271866.

The spelling of 135131921 in words is "one hundred thirty-five million, one hundred thirty-one thousand, nine hundred twenty-one".