815999964 has 48 divisors (see below), whose sum is σ = 2063583648. Its totient is φ = 249470208.

The previous prime is 815999963. The next prime is 815999981. The reversal of 815999964 is 469999518.

815999964 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 = 815999898 and 815999907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815999963) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7834 + ... + 41150.

It is an arithmetic number, because the mean of its divisors is an integer number (42991326).

Almost surely, 2^815999964 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 815999964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031791824).

815999964 is an abundant number, since it is smaller than the sum of its proper divisors (1247583684).

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

815999964 is a wasteful number, since it uses less digits than its factorization.

815999964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33494 (or 33492 counting only the distinct ones).

The product of its digits is 6298560, while the sum is 60.

The square root of 815999964 is about 28565.7130840454. The cubic root of 815999964 is about 934.4657319289.

The spelling of 815999964 in words is "eight hundred fifteen million, nine hundred ninety-nine thousand, nine hundred sixty-four".