1815745680 has 640 divisors, whose sum is σ = 7649510400. Its totient is φ = 387072000.

The previous prime is 1815745637. The next prime is 1815745681. The reversal of 1815745680 is 865475181.

1815745680 is a `hidden beast` number, since 1 + 8 + 15 + 74 + 568 + 0 = 666.

It is a super-3 number, since 3×1815745680³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1815745681) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 17977630 + ... + 17977730.

It is an arithmetic number, because the mean of its divisors is an integer number (11952360).

Almost surely, 2^1815745680 is an apocalyptic number.

1815745680 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 1815745680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3824755200).

1815745680 is an abundant number, since it is smaller than the sum of its proper divisors (5833764720).

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

1815745680 is a wasteful number, since it uses less digits than its factorization.

1815745680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 45.

The square root of 1815745680 is about 42611.5674435945. The cubic root of 1815745680 is about 1219.9770845826.

The spelling of 1815745680 in words is "one billion, eight hundred fifteen million, seven hundred forty-five thousand, six hundred eighty".