781649317 has 4 divisors (see below), whose sum is σ = 782725216. Its totient is φ = 780573420.

The previous prime is 781649299. The next prime is 781649327. The reversal of 781649317 is 713946187.

781649317 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 713946187 = 2293 ⋅311359.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-781649317 is a prime.

It is a super-2 number, since 2×781649317² = 1221951309533132978, which 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 (781649327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 536859 + ... + 538312.

It is an arithmetic number, because the mean of its divisors is an integer number (195681304).

Almost surely, 2^781649317 is an apocalyptic number.

It is an amenable number.

781649317 is a deficient number, since it is larger than the sum of its proper divisors (1075899).

781649317 is a wasteful number, since it uses less digits than its factorization.

781649317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1075898.

The product of its digits is 254016, while the sum is 46.

The square root of 781649317 is about 27957.9920058648. The cubic root of 781649317 is about 921.1647648829.

The spelling of 781649317 in words is "seven hundred eighty-one million, six hundred forty-nine thousand, three hundred seventeen".