1671531221 has 4 divisors (see below), whose sum is σ = 1674379392. Its totient is φ = 1668683052.

The previous prime is 1671531181. The next prime is 1671531283. The reversal of 1671531221 is 1221351761.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1671531221 - 2⁶ = 1671531157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1671533221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1423205 + ... + 1424378.

It is an arithmetic number, because the mean of its divisors is an integer number (418594848).

Almost surely, 2^1671531221 is an apocalyptic number.

It is an amenable number.

1671531221 is a deficient number, since it is larger than the sum of its proper divisors (2848171).

1671531221 is an equidigital number, since it uses as much as digits as its factorization.

1671531221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2848170.

The product of its digits is 2520, while the sum is 29.

The square root of 1671531221 is about 40884.3640160881. The cubic root of 1671531221 is about 1186.7834944297.

Adding to 1671531221 its reverse (1221351761), we get a palindrome (2892882982).

The spelling of 1671531221 in words is "one billion, six hundred seventy-one million, five hundred thirty-one thousand, two hundred twenty-one".