212601661 has 2 divisors, whose sum is σ = 212601662. Its totient is φ = 212601660.

The previous prime is 212601647. The next prime is 212601691. The reversal of 212601661 is 166106212.

212601661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 201810436 + 10791225 = 14206^2 + 3285^2 .

It is a cyclic number.

It is not a de Polignac number, because 212601661 - 2⁵ = 212601629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212601601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106300830 + 106300831.

It is an arithmetic number, because the mean of its divisors is an integer number (106300831).

Almost surely, 2^212601661 is an apocalyptic number.

It is an amenable number.

212601661 is a deficient number, since it is larger than the sum of its proper divisors (1).

212601661 is an equidigital number, since it uses as much as digits as its factorization.

212601661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 212601661 is about 14580.8662637033. The cubic root of 212601661 is about 596.8367421217.

Adding to 212601661 its reverse (166106212), we get a palindrome (378707873).

The spelling of 212601661 in words is "two hundred twelve million, six hundred one thousand, six hundred sixty-one".