212561 has 2 divisors, whose sum is σ = 212562. Its totient is φ = 212560.

The previous prime is 212557. The next prime is 212573. The reversal of 212561 is 165212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211600 + 961 = 460^2 + 31^2 .

It is a cyclic number.

It is not a de Polignac number, because 212561 - 2² = 212557 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a plaindrome in base 11.

It is not a weakly prime, because it can be changed into another prime (212501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106280 + 106281.

It is an arithmetic number, because the mean of its divisors is an integer number (106281).

2²¹²⁵⁶¹ is an apocalyptic number.

It is an amenable number.

212561 is a deficient number, since it is larger than the sum of its proper divisors (1).

212561 is an equidigital number, since it uses as much as digits as its factorization.

212561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120, while the sum is 17.

The square root of 212561 is about 461.0433819067. The cubic root of 212561 is about 59.6798690481.

Adding to 212561 its reverse (165212), we get a palindrome (377773).

The spelling of 212561 in words is "two hundred twelve thousand, five hundred sixty-one".