816456816399 has 32 divisors (see below), whose sum is σ = 1252044578304. Its totient is φ = 463579931520.

The previous prime is 816456816349. The next prime is 816456816403. The reversal of 816456816399 is 993618654618.

It is a Cunningham number, because it is equal to 903580²-1.

It is not a de Polignac number, because 816456816399 - 2¹⁷ = 816456685327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816456816349) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6260512 + ... + 6389594.

It is an arithmetic number, because the mean of its divisors is an integer number (39126393072).

Almost surely, 2^816456816399 is an apocalyptic number.

816456816399 is a deficient number, since it is larger than the sum of its proper divisors (435587761905).

816456816399 is a wasteful number, since it uses less digits than its factorization.

816456816399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131007.

The product of its digits is 67184640, while the sum is 66.

The spelling of 816456816399 in words is "eight hundred sixteen billion, four hundred fifty-six million, eight hundred sixteen thousand, three hundred ninety-nine".