13365807778 has 4 divisors (see below), whose sum is σ = 20048711670. Its totient is φ = 6682903888.

The previous prime is 13365807757. The next prime is 13365807781. The reversal of 13365807778 is 87770856331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87770856331 = 192553 ⋅455827.

It can be written as a sum of positive squares in only one way, i.e., 12468625569 + 897182209 = 111663^2 + 29953^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3341451943 + ... + 3341451946.

Almost surely, 2^13365807778 is an apocalyptic number.

13365807778 is a deficient number, since it is larger than the sum of its proper divisors (6682903892).

13365807778 is an equidigital number, since it uses as much as digits as its factorization.

13365807778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6682903891.

The product of its (nonzero) digits is 5927040, while the sum is 55.

The spelling of 13365807778 in words is "thirteen billion, three hundred sixty-five million, eight hundred seven thousand, seven hundred seventy-eight".