135670781 has 2 divisors, whose sum is σ = 135670782. Its totient is φ = 135670780.

The previous prime is 135670751. The next prime is 135670783. The reversal of 135670781 is 187076531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 118613881 + 17056900 = 10891^2 + 4130^2 .

It is a cyclic number.

It is not a de Polignac number, because 135670781 - 2²⁶ = 68561917 is a prime.

It is a super-2 number, since 2×135670781² = 36813121634299922, which contains 22 as substring.

Together with 135670783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135670783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67835390 + 67835391.

It is an arithmetic number, because the mean of its divisors is an integer number (67835391).

Almost surely, 2^135670781 is an apocalyptic number.

It is an amenable number.

135670781 is a deficient number, since it is larger than the sum of its proper divisors (1).

135670781 is an equidigital number, since it uses as much as digits as its factorization.

135670781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35280, while the sum is 38.

The square root of 135670781 is about 11647.7800889268. The cubic root of 135670781 is about 513.8410246342.

It can be divided in two parts, 13 and 5670781, that multiplied together give a triangular number (73720153 = T₁₂₁₄₂).

The spelling of 135670781 in words is "one hundred thirty-five million, six hundred seventy thousand, seven hundred eighty-one".