678612991 has 8 divisors (see below), whose sum is σ = 775951904. Its totient is φ = 581372640.

The previous prime is 678612989. The next prime is 678613027. The reversal of 678612991 is 199216876.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 678612991 - 2¹ = 678612989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (678612941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9240 + ... + 37981.

It is an arithmetic number, because the mean of its divisors is an integer number (96993988).

Almost surely, 2^678612991 is an apocalyptic number.

678612991 is a deficient number, since it is larger than the sum of its proper divisors (97338913).

678612991 is a wasteful number, since it uses less digits than its factorization.

678612991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49281.

The product of its digits is 326592, while the sum is 49.

The square root of 678612991 is about 26050.2013619857. The cubic root of 678612991 is about 878.7676409609.

The spelling of 678612991 in words is "six hundred seventy-eight million, six hundred twelve thousand, nine hundred ninety-one".