40521728 has 52 divisors (see below), whose sum is σ = 87381588. Its totient is φ = 18677760.

The previous prime is 40521721. The next prime is 40521769. The reversal of 40521728 is 82712504.

It can be written as a sum of positive squares in 2 ways, for example, as 1982464 + 38539264 = 1408^2 + 6208^2 .

It is a tau number, because it is divible by the number of its divisors (52).

It is a self number, because there is not a number n which added to its sum of digits gives 40521728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40521721) 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, 52868 + ... + 53628.

Almost surely, 2^40521728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 40521728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43690794).

40521728 is an abundant number, since it is smaller than the sum of its proper divisors (46859860).

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

40521728 is an equidigital number, since it uses as much as digits as its factorization.

40521728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 40521728 is about 6365.6679146811. The cubic root of 40521728 is about 343.4756749992.

The spelling of 40521728 in words is "forty million, five hundred twenty-one thousand, seven hundred twenty-eight".