816809280 has 224 divisors, whose sum is σ = 2983723776. Its totient is φ = 185450496.

The previous prime is 816809269. The next prime is 816809291. The reversal of 816809280 is 82908618.

It is an interprime number because it is at equal distance from previous prime (816809269) and next prime (816809291).

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1323532 + ... + 1324148.

Almost surely, 2^816809280 is an apocalyptic number.

816809280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816809280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1491861888).

816809280 is an abundant number, since it is smaller than the sum of its proper divisors (2166914496).

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

816809280 is a wasteful number, since it uses less digits than its factorization.

816809280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 841 (or 831 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 816809280 is about 28579.8754370973. The cubic root of 816809280 is about 934.7745669827.

The spelling of 816809280 in words is "eight hundred sixteen million, eight hundred nine thousand, two hundred eighty".