18878019938 has 4 divisors (see below), whose sum is σ = 28317029910. Its totient is φ = 9439009968.

The previous prime is 18878019929. The next prime is 18878019947. The reversal of 18878019938 is 83991087881.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83991087881 = 47 ⋅1787044423.

It is an interprime number because it is at equal distance from previous prime (18878019929) and next prime (18878019947).

It can be written as a sum of positive squares in only one way, i.e., 13927068169 + 4950951769 = 118013^2 + 70363^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4719504983 + ... + 4719504986.

Almost surely, 2^18878019938 is an apocalyptic number.

18878019938 is a deficient number, since it is larger than the sum of its proper divisors (9439009972).

18878019938 is an equidigital number, since it uses as much as digits as its factorization.

18878019938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9439009971.

The product of its (nonzero) digits is 6967296, while the sum is 62.

The spelling of 18878019938 in words is "eighteen billion, eight hundred seventy-eight million, nineteen thousand, nine hundred thirty-eight".