1671993221 has 4 divisors (see below), whose sum is σ = 1672075392. Its totient is φ = 1671911052.

The previous prime is 1671993199. The next prime is 1671993229. The reversal of 1671993221 is 1223991761.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1223991761 = 19 ⋅64420619.

It is a cyclic number.

It is not a de Polignac number, because 1671993221 - 2⁶ = 1671993157 is a prime.

It is a super-2 number, since 2×1671993221² = 5591122662139909682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1671993229) 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, 14546 + ... + 59628.

It is an arithmetic number, because the mean of its divisors is an integer number (418018848).

Almost surely, 2^1671993221 is an apocalyptic number.

It is an amenable number.

1671993221 is a deficient number, since it is larger than the sum of its proper divisors (82171).

1671993221 is an equidigital number, since it uses as much as digits as its factorization.

1671993221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82170.

The product of its digits is 40824, while the sum is 41.

The square root of 1671993221 is about 40890.0137075057. The cubic root of 1671993221 is about 1186.8928240193.

The spelling of 1671993221 in words is "one billion, six hundred seventy-one million, nine hundred ninety-three thousand, two hundred twenty-one".