268778996721 has 27 divisors (see below), whose sum is σ = 394844568417. Its totient is φ = 176186309760.

The previous prime is 268778996713. The next prime is 268778996771. The reversal of 268778996721 is 127699877862.

The square root of 268778996721 is 518439.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 114829488225 + 153949508496 = 338865^2 + 392364^2 .

It is not a de Polignac number, because 268778996721 - 2³ = 268778996713 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 268778996721.

It is not an unprimeable number, because it can be changed into a prime (268778996771) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 94872921 + ... + 94875753.

Almost surely, 2^268778996721 is an apocalyptic number.

268778996721 is the 518439-th square number.

268778996721 is the 259220-th centered octagonal number.

It is an amenable number.

268778996721 is a deficient number, since it is larger than the sum of its proper divisors (126065571696).

268778996721 is an frugal number, since it uses more digits than its factorization.

268778996721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5794 (or 2897 counting only the distinct ones).

The product of its digits is 256048128, while the sum is 72.

The spelling of 268778996721 in words is "two hundred sixty-eight billion, seven hundred seventy-eight million, nine hundred ninety-six thousand, seven hundred twenty-one".