781349137 has 4 divisors (see below), whose sum is σ = 785865780. Its totient is φ = 776832496.

The previous prime is 781349119. The next prime is 781349143. The reversal of 781349137 is 731943187.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 515789521 + 265559616 = 22711^2 + 16296^2 .

It is a cyclic number.

It is not a de Polignac number, because 781349137 - 2²⁷ = 647131409 is a prime.

It is a super-2 number, since 2×781349137² = 1221012947781289538, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 781349093 and 781349102.

It is not an unprimeable number, because it can be changed into a prime (781349237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2258062 + ... + 2258407.

It is an arithmetic number, because the mean of its divisors is an integer number (196466445).

Almost surely, 2^781349137 is an apocalyptic number.

It is an amenable number.

781349137 is a deficient number, since it is larger than the sum of its proper divisors (4516643).

781349137 is a wasteful number, since it uses less digits than its factorization.

781349137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4516642.

The product of its digits is 127008, while the sum is 43.

The square root of 781349137 is about 27952.6230790600. The cubic root of 781349137 is about 921.0468302210.

The spelling of 781349137 in words is "seven hundred eighty-one million, three hundred forty-nine thousand, one hundred thirty-seven".