18858349778 has 4 divisors (see below), whose sum is σ = 28287524670. Its totient is φ = 9429174888.

The previous prime is 18858349667. The next prime is 18858349859. The reversal of 18858349778 is 87794385881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87794385881 = 2389 ⋅36749429.

It can be written as a sum of positive squares in only one way, i.e., 18237692209 + 620657569 = 135047^2 + 24913^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4714587443 + ... + 4714587446.

Almost surely, 2^18858349778 is an apocalyptic number.

18858349778 is a deficient number, since it is larger than the sum of its proper divisors (9429174892).

18858349778 is an equidigital number, since it uses as much as digits as its factorization.

18858349778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9429174891.

The product of its digits is 108380160, while the sum is 68.

The spelling of 18858349778 in words is "eighteen billion, eight hundred fifty-eight million, three hundred forty-nine thousand, seven hundred seventy-eight".