1621843 has 2 divisors, whose sum is σ = 1621844. Its totient is φ = 1621842.

The previous prime is 1621819. The next prime is 1621849. The reversal of 1621843 is 3481261.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621843 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810921 + 810922.

It is an arithmetic number, because the mean of its divisors is an integer number (810922).

2^1621843 is an apocalyptic number.

1621843 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621843 is an equidigital number, since it uses as much as digits as its factorization.

1621843 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 25.

The square root of 1621843 is about 1273.5159991143. The cubic root of 1621843 is about 117.4905500171.

It can be divided in two parts, 16218 and 43, that added together give a palindrome (16261).

The spelling of 1621843 in words is "one million, six hundred twenty-one thousand, eight hundred forty-three".