4031561 has 2 divisors, whose sum is σ = 4031562. Its totient is φ = 4031560.

The previous prime is 4031543. The next prime is 4031563. The reversal of 4031561 is 1651304.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3041536 + 990025 = 1744^2 + 995^2 .

It is a cyclic number.

It is not a de Polignac number, because 4031561 - 2⁶ = 4031497 is a prime.

It is a Sophie Germain prime.

Together with 4031563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (4031563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2015780 + 2015781.

It is an arithmetic number, because the mean of its divisors is an integer number (2015781).

Almost surely, 2^4031561 is an apocalyptic number.

It is an amenable number.

4031561 is a deficient number, since it is larger than the sum of its proper divisors (1).

4031561 is an equidigital number, since it uses as much as digits as its factorization.

4031561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 4031561 is about 2007.8747470896. The cubic root of 4031561 is about 159.1565116310.

Adding to 4031561 its reverse (1651304), we get a palindrome (5682865).

The spelling of 4031561 in words is "four million, thirty-one thousand, five hundred sixty-one".