1620844399 has 2 divisors, whose sum is σ = 1620844400. Its totient is φ = 1620844398.

The previous prime is 1620844391. The next prime is 1620844403. The reversal of 1620844399 is 9934480261.

It is a strong prime.

It is an emirp because it is prime and its reverse (9934480261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1620844399 - 2³ = 1620844391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620844391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810422199 + 810422200.

It is an arithmetic number, because the mean of its divisors is an integer number (810422200).

Almost surely, 2^1620844399 is an apocalyptic number.

1620844399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620844399 is an equidigital number, since it uses as much as digits as its factorization.

1620844399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 373248, while the sum is 46.

The square root of 1620844399 is about 40259.7118593762. The cubic root of 1620844399 is about 1174.6643130999.

The spelling of 1620844399 in words is "one billion, six hundred twenty million, eight hundred forty-four thousand, three hundred ninety-nine".