1667881 has 2 divisors, whose sum is σ = 1667882. Its totient is φ = 1667880.

The previous prime is 1667873. The next prime is 1667899. The reversal of 1667881 is 1887661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1478656 + 189225 = 1216^2 + 435^2 .

It is a cyclic number.

It is not a de Polignac number, because 1667881 - 2³ = 1667873 is a prime.

It is a super-2 number, since 2×1667881² = 5563654060322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1667881.

It is not a weakly prime, because it can be changed into another prime (1667821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833940 + 833941.

It is an arithmetic number, because the mean of its divisors is an integer number (833941).

2^1667881 is an apocalyptic number.

It is an amenable number.

1667881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1667881 is an equidigital number, since it uses as much as digits as its factorization.

1667881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 37.

The square root of 1667881 is about 1291.4646723778. The cubic root of 1667881 is about 118.5918981865.

The spelling of 1667881 in words is "one million, six hundred sixty-seven thousand, eight hundred eighty-one".