1815320640 has 448 divisors, whose sum is σ = 6949440000. Its totient is φ = 401006592.

The previous prime is 1815320597. The next prime is 1815320669. The reversal of 1815320640 is 460235181.

It is a tau number, because it is divible by the number of its divisors (448).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1815320598 and 1815320607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12183286 + ... + 12183434.

Almost surely, 2^1815320640 is an apocalyptic number.

1815320640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1815320640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3474720000).

1815320640 is an abundant number, since it is smaller than the sum of its proper divisors (5134119360).

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

1815320640 is a wasteful number, since it uses less digits than its factorization.

1815320640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 1815320640 is about 42606.5797735514. The cubic root of 1815320640 is about 1219.8818841126.

The spelling of 1815320640 in words is "one billion, eight hundred fifteen million, three hundred twenty thousand, six hundred forty".