1671921 has 10 divisors (see below), whose sum is σ = 2497682. Its totient is φ = 1114560.

The previous prime is 1671907. The next prime is 1671941. The reversal of 1671921 is 1291761.

It can be written as a sum of positive squares in only one way, i.e., 1166400 + 505521 = 1080^2 + 711^2 .

It is not a de Polignac number, because 1671921 - 2¹¹ = 1669873 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1671941) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 10240 + ... + 10401.

2^1671921 is an apocalyptic number.

It is an amenable number.

1671921 is a deficient number, since it is larger than the sum of its proper divisors (825761).

1671921 is an equidigital number, since it uses as much as digits as its factorization.

1671921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20653 (or 20644 counting only the distinct ones).

The product of its digits is 756, while the sum is 27.

The square root of 1671921 is about 1293.0278419276. The cubic root of 1671921 is about 118.6875734672.

The spelling of 1671921 in words is "one million, six hundred seventy-one thousand, nine hundred twenty-one".