135440621 has 2 divisors, whose sum is σ = 135440622. Its totient is φ = 135440620.

The previous prime is 135440587. The next prime is 135440639. The reversal of 135440621 is 126044531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 112063396 + 23377225 = 10586^2 + 4835^2 .

It is a cyclic number.

It is not a de Polignac number, because 135440621 - 2¹⁰ = 135439597 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135440321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67720310 + 67720311.

It is an arithmetic number, because the mean of its divisors is an integer number (67720311).

Almost surely, 2^135440621 is an apocalyptic number.

It is an amenable number.

135440621 is a deficient number, since it is larger than the sum of its proper divisors (1).

135440621 is an equidigital number, since it uses as much as digits as its factorization.

135440621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 135440621 is about 11637.8959008921. The cubic root of 135440621 is about 513.5502899845.

The spelling of 135440621 in words is "one hundred thirty-five million, four hundred forty thousand, six hundred twenty-one".