819138497 has 4 divisors (see below), whose sum is σ = 819501780. Its totient is φ = 818775216.

The previous prime is 819138457. The next prime is 819138511. The reversal of 819138497 is 794831918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 794831918 = 2 ⋅397415959.

It can be written as a sum of positive squares in 2 ways, for example, as 17172736 + 801965761 = 4144^2 + 28319^2 .

It is a cyclic number.

It is not a de Polignac number, because 819138497 - 2¹⁴ = 819122113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (819138427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178238 + ... + 182775.

It is an arithmetic number, because the mean of its divisors is an integer number (204875445).

Almost surely, 2^819138497 is an apocalyptic number.

It is an amenable number.

819138497 is a deficient number, since it is larger than the sum of its proper divisors (363283).

819138497 is a wasteful number, since it uses less digits than its factorization.

819138497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363282.

The product of its digits is 435456, while the sum is 50.

The square root of 819138497 is about 28620.5956786367. The cubic root of 819138497 is about 935.6622595141.

The spelling of 819138497 in words is "eight hundred nineteen million, one hundred thirty-eight thousand, four hundred ninety-seven".