1967821 has 2 divisors, whose sum is σ = 1967822. Its totient is φ = 1967820.

The previous prime is 1967813. The next prime is 1967851. The reversal of 1967821 is 1287691.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1932100 + 35721 = 1390^2 + 189^2 .

It is an emirp because it is prime and its reverse (1287691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1967821 - 2³ = 1967813 is a prime.

1967821 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1967851) 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, 983910 + 983911.

It is an arithmetic number, because the mean of its divisors is an integer number (983911).

2^1967821 is an apocalyptic number.

It is an amenable number.

1967821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1967821 is an equidigital number, since it uses as much as digits as its factorization.

1967821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 34.

The square root of 1967821 is about 1402.7904333863. The cubic root of 1967821 is about 125.3127316057.

The spelling of 1967821 in words is "one million, nine hundred sixty-seven thousand, eight hundred twenty-one".