4002540561 has 10 divisors (see below), whose sum is σ = 5979103922. Its totient is φ = 2668360320.

The previous prime is 4002540557. The next prime is 4002540583. The reversal of 4002540561 is 1650452004.

4002540561 is a `hidden beast` number, since 40 + 0 + 25 + 40 + 561 = 666.

4002540561 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 2182664961 + 1819875600 = 46719^2 + 42660^2 .

It is not a de Polignac number, because 4002540561 - 2² = 4002540557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4002540161) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 24706960 + ... + 24707121.

Almost surely, 2^4002540561 is an apocalyptic number.

It is an amenable number.

4002540561 is a deficient number, since it is larger than the sum of its proper divisors (1976563361).

4002540561 is an equidigital number, since it uses as much as digits as its factorization.

4002540561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49414093 (or 49414084 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 4002540561 is about 63265.6349134346. The cubic root of 4002540561 is about 1587.7370549422.

Adding to 4002540561 its reverse (1650452004), we get a palindrome (5652992565).

The spelling of 4002540561 in words is "four billion, two million, five hundred forty thousand, five hundred sixty-one".