816312321 has 12 divisors (see below), whose sum is σ = 1286310480. Its totient is φ = 494734680.

The previous prime is 816312319. The next prime is 816312323. The reversal of 816312321 is 123213618.

It is a happy number.

816312321 is a `hidden beast` number, since 8 + 1 + 631 + 2 + 3 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (816312319) and next prime (816312323).

It is not a de Polignac number, because 816312321 - 2¹ = 816312319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (816312323) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4122691 + ... + 4122888.

It is an arithmetic number, because the mean of its divisors is an integer number (107192540).

Almost surely, 2^816312321 is an apocalyptic number.

It is an amenable number.

816312321 is a deficient number, since it is larger than the sum of its proper divisors (469998159).

816312321 is a wasteful number, since it uses less digits than its factorization.

816312321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8245596 (or 8245593 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 816312321 is about 28571.1799021321. The cubic root of 816312321 is about 934.5849515733.

Adding to 816312321 its reverse (123213618), we get a palindrome (939525939).

The spelling of 816312321 in words is "eight hundred sixteen million, three hundred twelve thousand, three hundred twenty-one".