815505408 has 140 divisors (see below), whose sum is σ = 2438281890. Its totient is φ = 271613952.

The previous prime is 815505391. The next prime is 815505421. The reversal of 815505408 is 804505518.

It can be written as a sum of positive squares in only one way, i.e., 454201344 + 361304064 = 21312^2 + 19008^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 662938 + ... + 664166.

Almost surely, 2^815505408 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 815505408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1219140945).

815505408 is an abundant number, since it is smaller than the sum of its proper divisors (1622776482).

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

815505408 is an equidigital number, since it uses as much as digits as its factorization.

815505408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1267 (or 1234 counting only the distinct ones).

The product of its (nonzero) digits is 32000, while the sum is 36.

The square root of 815505408 is about 28557.0553103782. The cubic root of 815505408 is about 934.2769087871.

The spelling of 815505408 in words is "eight hundred fifteen million, five hundred five thousand, four hundred eight".