678521722 has 4 divisors (see below), whose sum is σ = 1017782586. Its totient is φ = 339260860.

The previous prime is 678521719. The next prime is 678521761. The reversal of 678521722 is 227125876.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 463928521 + 214593201 = 21539^2 + 14649^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 169630429 + ... + 169630432.

Almost surely, 2^678521722 is an apocalyptic number.

678521722 is a deficient number, since it is larger than the sum of its proper divisors (339260864).

678521722 is a wasteful number, since it uses less digits than its factorization.

678521722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339260863.

The product of its digits is 94080, while the sum is 40.

The square root of 678521722 is about 26048.4495123990. The cubic root of 678521722 is about 878.7282430317.

The spelling of 678521722 in words is "six hundred seventy-eight million, five hundred twenty-one thousand, seven hundred twenty-two".