678553261978 has 4 divisors (see below), whose sum is σ = 1017829892970. Its totient is φ = 339276630988.

The previous prime is 678553261961. The next prime is 678553262027. The reversal of 678553261978 is 879162355876.

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., 670307350729 + 8245911249 = 818723^2 + 90807^2 .

It is a Smith number, since the sum of its digits (67) 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, 169638315493 + ... + 169638315496.

Almost surely, 2^678553261978 is an apocalyptic number.

678553261978 is a deficient number, since it is larger than the sum of its proper divisors (339276630992).

678553261978 is a wasteful number, since it uses less digits than its factorization.

678553261978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339276630991.

The product of its digits is 152409600, while the sum is 67.

The spelling of 678553261978 in words is "six hundred seventy-eight billion, five hundred fifty-three million, two hundred sixty-one thousand, nine hundred seventy-eight".