268391978 has 4 divisors (see below), whose sum is σ = 402587970. Its totient is φ = 134195988.

The previous prime is 268391957. The next prime is 268391983. The reversal of 268391978 is 879193862.

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., 254945089 + 13446889 = 15967^2 + 3667^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67097993 + ... + 67097996.

Almost surely, 2^268391978 is an apocalyptic number.

268391978 is a deficient number, since it is larger than the sum of its proper divisors (134195992).

268391978 is a wasteful number, since it uses less digits than its factorization.

268391978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134195991.

The product of its digits is 1306368, while the sum is 53.

The square root of 268391978 is about 16382.6731030073. The cubic root of 268391978 is about 645.0447482125.

The spelling of 268391978 in words is "two hundred sixty-eight million, three hundred ninety-one thousand, nine hundred seventy-eight".