18520557778 has 8 divisors (see below), whose sum is σ = 28426902768. Its totient is φ = 9044923524.

The previous prime is 18520557773. The next prime is 18520557779. The reversal of 18520557778 is 87775502581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×18520557778² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18520557773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107677576 + ... + 107677747.

It is an arithmetic number, because the mean of its divisors is an integer number (3553362846).

Almost surely, 2^18520557778 is an apocalyptic number.

18520557778 is a deficient number, since it is larger than the sum of its proper divisors (9906344990).

18520557778 is a wasteful number, since it uses less digits than its factorization.

18520557778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215355368.

The product of its (nonzero) digits is 5488000, while the sum is 55.

The spelling of 18520557778 in words is "eighteen billion, five hundred twenty million, five hundred fifty-seven thousand, seven hundred seventy-eight".