819020888138 has 4 divisors (see below), whose sum is σ = 1228531332210. Its totient is φ = 409510444068.

The previous prime is 819020888137. The next prime is 819020888183. The reversal of 819020888138 is 831888020918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 701394525049 + 117626363089 = 837493^2 + 342967^2 .

It is not an unprimeable number, because it can be changed into a prime (819020888137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204755222033 + ... + 204755222036.

Almost surely, 2^819020888138 is an apocalyptic number.

819020888138 is a deficient number, since it is larger than the sum of its proper divisors (409510444072).

819020888138 is a wasteful number, since it uses less digits than its factorization.

819020888138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409510444071.

The product of its (nonzero) digits is 1769472, while the sum is 56.

The spelling of 819020888138 in words is "eight hundred nineteen billion, twenty million, eight hundred eighty-eight thousand, one hundred thirty-eight".