1620983809 has 2 divisors, whose sum is σ = 1620983810. Its totient is φ = 1620983808.

The previous prime is 1620983783. The next prime is 1620983827. The reversal of 1620983809 is 9083890261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1430957584 + 190026225 = 37828^2 + 13785^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620983809 is a prime.

It is not a weakly prime, because it can be changed into another prime (1620983839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810491904 + 810491905.

It is an arithmetic number, because the mean of its divisors is an integer number (810491905).

Almost surely, 2^1620983809 is an apocalyptic number.

It is an amenable number.

1620983809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620983809 is an equidigital number, since it uses as much as digits as its factorization.

1620983809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 1620983809 is about 40261.4432056279. The cubic root of 1620983809 is about 1174.6979900437.

The spelling of 1620983809 in words is "one billion, six hundred twenty million, nine hundred eighty-three thousand, eight hundred nine".