1815720396 has 24 divisors (see below), whose sum is σ = 4841921280. Its totient is φ = 518777232.

The previous prime is 1815720373. The next prime is 1815720433. The reversal of 1815720396 is 6930275181.

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

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10807776 + ... + 10807943.

It is an arithmetic number, because the mean of its divisors is an integer number (201746720).

Almost surely, 2^1815720396 is an apocalyptic number.

It is an amenable number.

1815720396 is an abundant number, since it is smaller than the sum of its proper divisors (3026200884).

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

1815720396 is a wasteful number, since it uses less digits than its factorization.

1815720396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21615733 (or 21615731 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 1815720396 is about 42611.2707625576. The cubic root of 1815720396 is about 1219.9714218872.

The spelling of 1815720396 in words is "one billion, eight hundred fifteen million, seven hundred twenty thousand, three hundred ninety-six".