135939507421 has 4 divisors (see below), whose sum is σ = 143935949052. Its totient is φ = 127943065792.

The previous prime is 135939507397. The next prime is 135939507433. The reversal of 135939507421 is 124705939531.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 124705939531 = 103 ⋅1210737277.

It can be written as a sum of positive squares in 2 ways, for example, as 53118725625 + 82820781796 = 230475^2 + 287786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135939507421 is a prime.

It is a super-2 number, since 2×135939507421² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135939507481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3998220790 + ... + 3998220823.

It is an arithmetic number, because the mean of its divisors is an integer number (35983987263).

Almost surely, 2^135939507421 is an apocalyptic number.

It is an amenable number.

135939507421 is a deficient number, since it is larger than the sum of its proper divisors (7996441631).

135939507421 is an equidigital number, since it uses as much as digits as its factorization.

135939507421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7996441630.

The product of its (nonzero) digits is 1020600, while the sum is 49.

The spelling of 135939507421 in words is "one hundred thirty-five billion, nine hundred thirty-nine million, five hundred seven thousand, four hundred twenty-one".