4081561 has 16 divisors (see below), whose sum is σ = 4780800. Its totient is φ = 3445200.

The previous prime is 4081549. The next prime is 4081579. The reversal of 4081561 is 1651804.

4081561 = 55² + 56² + ... + 231².

It is not a de Polignac number, because 4081561 - 2¹⁹ = 3557273 is a prime.

It is a Duffinian number.

4081561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (4081501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12166 + ... + 12496.

It is an arithmetic number, because the mean of its divisors is an integer number (298800).

Almost surely, 2^4081561 is an apocalyptic number.

4081561 is the 904-th centered decagonal number.

It is an amenable number.

4081561 is a deficient number, since it is larger than the sum of its proper divisors (699239).

4081561 is a wasteful number, since it uses less digits than its factorization.

4081561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 4081561 is about 2020.2873557987. The cubic root of 4081561 is about 159.8117708355.

The spelling of 4081561 in words is "four million, eighty-one thousand, five hundred sixty-one".