2117561 has 2 divisors, whose sum is σ = 2117562. Its totient is φ = 2117560.

The previous prime is 2117539. The next prime is 2117573. The reversal of 2117561 is 1657112.

2117561 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., 1547536 + 570025 = 1244^2 + 755^2 .

It is a cyclic number.

It is not a de Polignac number, because 2117561 - 2⁶ = 2117497 is a prime.

It is a d-powerful number, because it can be written as 2⁷ + 1 + 1 + 7⁶ + 5⁹ + 6⁶ + 1 .

It is not a weakly prime, because it can be changed into another prime (2117501) 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, 1058780 + 1058781.

It is an arithmetic number, because the mean of its divisors is an integer number (1058781).

2^2117561 is an apocalyptic number.

It is an amenable number.

2117561 is a deficient number, since it is larger than the sum of its proper divisors (1).

2117561 is an equidigital number, since it uses as much as digits as its factorization.

2117561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 420, while the sum is 23.

The square root of 2117561 is about 1455.1841807826. The cubic root of 2117561 is about 128.4138824546.

The spelling of 2117561 in words is "two million, one hundred seventeen thousand, five hundred sixty-one".