2645561 has 2 divisors, whose sum is σ = 2645562. Its totient is φ = 2645560.

The previous prime is 2645551. The next prime is 2645567. The reversal of 2645561 is 1655462.

2645561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2119936 + 525625 = 1456^2 + 725^2 .

It is a cyclic number.

It is not a de Polignac number, because 2645561 - 2¹⁴ = 2629177 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p₁₉₂₉₅₃ and since 2645561 and 192953 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (2645567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1322780 + 1322781.

It is an arithmetic number, because the mean of its divisors is an integer number (1322781).

2^2645561 is an apocalyptic number.

It is an amenable number.

2645561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2645561 is an equidigital number, since it uses as much as digits as its factorization.

2645561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7200, while the sum is 29.

The square root of 2645561 is about 1626.5180601518. The cubic root of 2645561 is about 138.3054391265.

Subtracting from 2645561 its reverse (1655462), we obtain a palindrome (990099).

The spelling of 2645561 in words is "two million, six hundred forty-five thousand, five hundred sixty-one".