678749917 has 4 divisors (see below), whose sum is σ = 678828960. Its totient is φ = 678670876.

The previous prime is 678749891. The next prime is 678749947. The reversal of 678749917 is 719947876.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-678749917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678749947) 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, 24817 + ... + 44422.

It is an arithmetic number, because the mean of its divisors is an integer number (169707240).

Almost surely, 2^678749917 is an apocalyptic number.

It is an amenable number.

678749917 is a deficient number, since it is larger than the sum of its proper divisors (79043).

678749917 is an equidigital number, since it uses as much as digits as its factorization.

678749917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79042.

The product of its digits is 5334336, while the sum is 58.

The square root of 678749917 is about 26052.8293473089. The cubic root of 678749917 is about 878.8267409426.

The spelling of 678749917 in words is "six hundred seventy-eight million, seven hundred forty-nine thousand, nine hundred seventeen".