816456816400 has 45 divisors (see below), whose sum is σ = 1961580919381. Its totient is φ = 326575497920.

The previous prime is 816456816349. The next prime is 816456816403. The reversal of 816456816400 is 4618654618.

The square root of 816456816400 is 903580.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 293924453904 + 522532362496 = 542148^2 + 722864^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816456816403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 18049011 + ... + 18094189.

Almost surely, 2^816456816400 is an apocalyptic number.

816456816400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

816456816400 is the 903580-th square number.

It is an amenable number.

816456816400 is an abundant number, since it is smaller than the sum of its proper divisors (1145124102981).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

816456816400 is an frugal number, since it uses more digits than its factorization.

816456816400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90376 (or 45186 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 49.

Multiplying 816456816400 by its sum of digits (49), we get a square (40006384003600 = 6325060²).

The spelling of 816456816400 in words is "eight hundred sixteen billion, four hundred fifty-six million, eight hundred sixteen thousand, four hundred".