1621849 has 2 divisors, whose sum is σ = 1621850. Its totient is φ = 1621848.

The previous prime is 1621843. The next prime is 1621861. The reversal of 1621849 is 9481261.

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., 1550025 + 71824 = 1245^2 + 268^2 .

It is an emirp because it is prime and its reverse (9481261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621849 - 2⁷ = 1621721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621849.

It is not a weakly prime, because it can be changed into another prime (1621843) 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, 810924 + 810925.

It is an arithmetic number, because the mean of its divisors is an integer number (810925).

2^1621849 is an apocalyptic number.

It is an amenable number.

1621849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621849 is an equidigital number, since it uses as much as digits as its factorization.

1621849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 31.

The square root of 1621849 is about 1273.5183547951. The cubic root of 1621849 is about 117.4906949022.

The spelling of 1621849 in words is "one million, six hundred twenty-one thousand, eight hundred forty-nine".