816639540 has 96 divisors (see below), whose sum is σ = 2445375744. Its totient is φ = 202905600.

The previous prime is 816639533. The next prime is 816639563. The reversal of 816639540 is 45936618.

816639540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 816639492 and 816639501.

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, 99057 + ... + 106983.

It is an arithmetic number, because the mean of its divisors is an integer number (25472664).

Almost surely, 2^816639540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816639540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1222687872).

816639540 is an abundant number, since it is smaller than the sum of its proper divisors (1628736204).

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

816639540 is a wasteful number, since it uses less digits than its factorization.

816639540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8057 (or 8055 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 816639540 is about 28576.9057107308. The cubic root of 816639540 is about 934.7098110961.

The spelling of 816639540 in words is "eight hundred sixteen million, six hundred thirty-nine thousand, five hundred forty".