678940690 has 8 divisors (see below), whose sum is σ = 1222093260. Its totient is φ = 271576272.

The previous prime is 678940687. The next prime is 678940697. The reversal of 678940690 is 96049876.

It can be written as a sum of positive squares in 2 ways, for example, as 663629121 + 15311569 = 25761^2 + 3913^2 .

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

It is a super-2 number, since 2×678940690² = 921920921075352200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (678940697) 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, 33947025 + ... + 33947044.

Almost surely, 2^678940690 is an apocalyptic number.

678940690 is a deficient number, since it is larger than the sum of its proper divisors (543152570).

678940690 is a wasteful number, since it uses less digits than its factorization.

678940690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67894076.

The product of its (nonzero) digits is 653184, while the sum is 49.

The square root of 678940690 is about 26056.4903622879. The cubic root of 678940690 is about 878.9090691092.

The spelling of 678940690 in words is "six hundred seventy-eight million, nine hundred forty thousand, six hundred ninety".