18701778778 has 16 divisors (see below), whose sum is σ = 29705420520. Its totient is φ = 8800068096.

The previous prime is 18701778773. The next prime is 18701778787. The reversal of 18701778778 is 87787710781.

It can be written as a sum of positive squares in 4 ways, for example, as 18634161049 + 67617729 = 136507^2 + 8223^2 .

It is a super-2 number, since 2×18701778778² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18701778773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 624328 + ... + 653596.

Almost surely, 2^18701778778 is an apocalyptic number.

18701778778 is a deficient number, since it is larger than the sum of its proper divisors (11003641742).

18701778778 is a wasteful number, since it uses less digits than its factorization.

18701778778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48081.

The product of its (nonzero) digits is 8605184, while the sum is 61.

The spelling of 18701778778 in words is "eighteen billion, seven hundred one million, seven hundred seventy-eight thousand, seven hundred seventy-eight".