135249391721 has 2 divisors, whose sum is σ = 135249391722. Its totient is φ = 135249391720.

The previous prime is 135249391681. The next prime is 135249391733. The reversal of 135249391721 is 127193942531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125376187225 + 9873204496 = 354085^2 + 99364^2 .

It is an emirp because it is prime and its reverse (127193942531) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135249391721 is a prime.

It is not a weakly prime, because it can be changed into another prime (135249391021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67624695860 + 67624695861.

It is an arithmetic number, because the mean of its divisors is an integer number (67624695861).

Almost surely, 2^135249391721 is an apocalyptic number.

It is an amenable number.

135249391721 is a deficient number, since it is larger than the sum of its proper divisors (1).

135249391721 is an equidigital number, since it uses as much as digits as its factorization.

135249391721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 47.

The spelling of 135249391721 in words is "one hundred thirty-five billion, two hundred forty-nine million, three hundred ninety-one thousand, seven hundred twenty-one".