781284137 has 2 divisors, whose sum is σ = 781284138. Its totient is φ = 781284136.

The previous prime is 781284121. The next prime is 781284139. The reversal of 781284137 is 731482187.

781284137 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553002256 + 228281881 = 23516^2 + 15109^2 .

It is an emirp because it is prime and its reverse (731482187) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 781284137 - 2⁴ = 781284121 is a prime.

It is a super-2 number, since 2×781284137² = 1220809805455669538, which contains 22 as substring.

Together with 781284139, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 781284094 and 781284103.

It is not a weakly prime, because it can be changed into another prime (781284139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390642068 + 390642069.

It is an arithmetic number, because the mean of its divisors is an integer number (390642069).

Almost surely, 2^781284137 is an apocalyptic number.

It is an amenable number.

781284137 is a deficient number, since it is larger than the sum of its proper divisors (1).

781284137 is an equidigital number, since it uses as much as digits as its factorization.

781284137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75264, while the sum is 41.

The square root of 781284137 is about 27951.4603732971. The cubic root of 781284137 is about 921.0212890549.

The spelling of 781284137 in words is "seven hundred eighty-one million, two hundred eighty-four thousand, one hundred thirty-seven".