819778691397 has 8 divisors (see below), whose sum is σ = 1094386024480. Its totient is φ = 545845242960.

The previous prime is 819778691383. The next prime is 819778691411. The reversal of 819778691397 is 793196877918.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (819778691383) and next prime (819778691411).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 819778691397 - 2³⁸ = 544900784453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (819778691317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 168468322 + ... + 168473187.

It is an arithmetic number, because the mean of its divisors is an integer number (136798253060).

Almost surely, 2^819778691397 is an apocalyptic number.

It is an amenable number.

819778691397 is a deficient number, since it is larger than the sum of its proper divisors (274607333083).

819778691397 is a wasteful number, since it uses less digits than its factorization.

819778691397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336942323.

The product of its digits is 288054144, while the sum is 75.

The spelling of 819778691397 in words is "eight hundred nineteen billion, seven hundred seventy-eight million, six hundred ninety-one thousand, three hundred ninety-seven".