1671533221 has 2 divisors, whose sum is σ = 1671533222. Its totient is φ = 1671533220.

The previous prime is 1671533209. The next prime is 1671533231. The reversal of 1671533221 is 1223351761.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 938748321 + 732784900 = 30639^2 + 27070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1671533221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1671533231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 835766610 + 835766611.

It is an arithmetic number, because the mean of its divisors is an integer number (835766611).

Almost surely, 2^1671533221 is an apocalyptic number.

It is an amenable number.

1671533221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1671533221 is an equidigital number, since it uses as much as digits as its factorization.

1671533221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 31.

The square root of 1671533221 is about 40884.3884753093. The cubic root of 1671533221 is about 1186.7839677614.

Adding to 1671533221 its reverse (1223351761), we get a palindrome (2894884982).

The spelling of 1671533221 in words is "one billion, six hundred seventy-one million, five hundred thirty-three thousand, two hundred twenty-one".