1838128778 has 4 divisors (see below), whose sum is σ = 2757193170. Its totient is φ = 919064388.

The previous prime is 1838128771. The next prime is 1838128807. The reversal of 1838128778 is 8778218381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8778218381 = 233 ⋅37674757.

It can be written as a sum of positive squares in only one way, i.e., 1752510769 + 85618009 = 41863^2 + 9253^2 .

It is not an unprimeable number, because it can be changed into a prime (1838128771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459532193 + ... + 459532196.

Almost surely, 2^1838128778 is an apocalyptic number.

1838128778 is a deficient number, since it is larger than the sum of its proper divisors (919064392).

1838128778 is an equidigital number, since it uses as much as digits as its factorization.

1838128778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919064391.

The product of its digits is 1204224, while the sum is 53.

The square root of 1838128778 is about 42873.4040869162. The cubic root of 1838128778 is about 1224.9696014670.

The spelling of 1838128778 in words is "one billion, eight hundred thirty-eight million, one hundred twenty-eight thousand, seven hundred seventy-eight".