781116649 has 4 divisors (see below), whose sum is σ = 782880336. Its totient is φ = 779352964.

The previous prime is 781116607. The next prime is 781116659. The reversal of 781116649 is 946611187.

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: 946611187 = 17 ⋅55683011.

It is a cyclic number.

It is not a de Polignac number, because 781116649 - 2⁷ = 781116521 is a prime.

It is a super-2 number, since 2×781116649² = 1220286438689978402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (781116659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 881179 + ... + 882064.

It is an arithmetic number, because the mean of its divisors is an integer number (195720084).

Almost surely, 2^781116649 is an apocalyptic number.

It is an amenable number.

781116649 is a deficient number, since it is larger than the sum of its proper divisors (1763687).

781116649 is a wasteful number, since it uses less digits than its factorization.

781116649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1763686.

The product of its digits is 72576, while the sum is 43.

The square root of 781116649 is about 27948.4641617388. The cubic root of 781116649 is about 920.9554696213.

The spelling of 781116649 in words is "seven hundred eighty-one million, one hundred sixteen thousand, six hundred forty-nine".