815123440 has 40 divisors (see below), whose sum is σ = 1897008048. Its totient is φ = 325731840.

The previous prime is 815123417. The next prime is 815123443. The reversal of 815123440 is 44321518.

815123440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 815123399 and 815123408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815123443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88660 + ... + 97420.

Almost surely, 2^815123440 is an apocalyptic number.

815123440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

815123440 is an abundant number, since it is smaller than the sum of its proper divisors (1081884608).

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

815123440 is a wasteful number, since it uses less digits than its factorization.

815123440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9937 (or 9931 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 815123440 is about 28550.3667226885. The cubic root of 815123440 is about 934.1310198658.

Adding to 815123440 its reverse (44321518), we get a palindrome (859444958).

The spelling of 815123440 in words is "eight hundred fifteen million, one hundred twenty-three thousand, four hundred forty".