2581664040 has 96 divisors (see below), whose sum is σ = 8444035080. Its totient is φ = 684043776.

The previous prime is 2581664039. The next prime is 2581664051. The reversal of 2581664040 is 404661852.

2581664040 is a `hidden beast` number, since 2 + 5 + 8 + 1 + 6 + 640 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2298818916 + 282845124 = 47946^2 + 16818^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 2581663986 and 2581664004.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33682 + ... + 79358.

Almost surely, 2^2581664040 is an apocalyptic number.

2581664040 is a gapful number since it is divisible by the number (20) 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 2581664040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4222017540).

2581664040 is an abundant number, since it is smaller than the sum of its proper divisors (5862371040).

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

2581664040 is a wasteful number, since it uses less digits than its factorization.

2581664040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45851 (or 45844 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 2581664040 is about 50810.0781341655. The cubic root of 2581664040 is about 1371.8287758738.

The spelling of 2581664040 in words is "two billion, five hundred eighty-one million, six hundred sixty-four thousand, forty".