1999445797 has 2 divisors, whose sum is σ = 1999445798. Its totient is φ = 1999445796.

The previous prime is 1999445761. The next prime is 1999445807. The reversal of 1999445797 is 7975449991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1866758436 + 132687361 = 43206^2 + 11519^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999445797 - 2²⁷ = 1865228069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999445197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999722898 + 999722899.

It is an arithmetic number, because the mean of its divisors is an integer number (999722899).

Almost surely, 2^1999445797 is an apocalyptic number.

It is an amenable number.

1999445797 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999445797 is an equidigital number, since it uses as much as digits as its factorization.

1999445797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25719120, while the sum is 64.

The square root of 1999445797 is about 44715.1629427871. The cubic root of 1999445797 is about 1259.8046638064.

The spelling of 1999445797 in words is "one billion, nine hundred ninety-nine million, four hundred forty-five thousand, seven hundred ninety-seven".