4011561 has 12 divisors (see below), whose sum is σ = 5822388. Its totient is φ = 2661504.

The previous prime is 4011559. The next prime is 4011583. The reversal of 4011561 is 1651104.

It can be written as a sum of positive squares in 2 ways, for example, as 2205225 + 1806336 = 1485^2 + 1344^2 .

It is not a de Polignac number, because 4011561 - 2¹ = 4011559 is a prime.

It is a Curzon number.

4011561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (4011551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1141 + ... + 3053.

It is an arithmetic number, because the mean of its divisors is an integer number (485199).

Almost surely, 2^4011561 is an apocalyptic number.

It is an amenable number.

4011561 is a deficient number, since it is larger than the sum of its proper divisors (1810827).

4011561 is a wasteful number, since it uses less digits than its factorization.

4011561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2152 (or 2149 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 4011561 is about 2002.8881646263. Note that the first 3 decimals coincide. The cubic root of 4011561 is about 158.8928909579.

Adding to 4011561 its reverse (1651104), we get a palindrome (5662665).

The spelling of 4011561 in words is "four million, eleven thousand, five hundred sixty-one".