40128640 has 32 divisors (see below), whose sum is σ = 95934060. Its totient is φ = 16051200.

The previous prime is 40128631. The next prime is 40128643. The reversal of 40128640 is 4682104.

It can be written as a sum of positive squares in 2 ways, for example, as 39841344 + 287296 = 6312^2 + 536^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×40128640² = 3220615496499200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (40128643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30711 + ... + 31990.

Almost surely, 2^40128640 is an apocalyptic number.

40128640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

40128640 is an abundant number, since it is smaller than the sum of its proper divisors (55805420).

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

40128640 is an equidigital number, since it uses as much as digits as its factorization.

40128640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62720 (or 62708 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 40128640 is about 6334.7170418259. The cubic root of 40128640 is about 342.3614158636.

The spelling of 40128640 in words is "forty million, one hundred twenty-eight thousand, six hundred forty".