221660837 has 2 divisors, whose sum is σ = 221660838. Its totient is φ = 221660836.

The previous prime is 221660797. The next prime is 221660839. The reversal of 221660837 is 738066122.

It is a happy number.

221660837 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., 111809476 + 109851361 = 10574^2 + 10481^2 .

It is a cyclic number.

It is not a de Polignac number, because 221660837 - 2¹⁰ = 221659813 is a prime.

Together with 221660839, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 221660797 and 221660806.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221660839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110830418 + 110830419.

It is an arithmetic number, because the mean of its divisors is an integer number (110830419).

Almost surely, 2^221660837 is an apocalyptic number.

It is an amenable number.

221660837 is a deficient number, since it is larger than the sum of its proper divisors (1).

221660837 is an equidigital number, since it uses as much as digits as its factorization.

221660837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 221660837 is about 14888.2785102912. The cubic root of 221660837 is about 605.1963818459.

The spelling of 221660837 in words is "two hundred twenty-one million, six hundred sixty thousand, eight hundred thirty-seven".