1990859813 has 2 divisors, whose sum is σ = 1990859814. Its totient is φ = 1990859812.

The previous prime is 1990859807. The next prime is 1990859873. The reversal of 1990859813 is 3189580991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1979983009 + 10876804 = 44497^2 + 3298^2 .

It is an emirp because it is prime and its reverse (3189580991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1990859813 - 2⁴ = 1990859797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1990859873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995429906 + 995429907.

It is an arithmetic number, because the mean of its divisors is an integer number (995429907).

Almost surely, 2^1990859813 is an apocalyptic number.

It is an amenable number.

1990859813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990859813 is an equidigital number, since it uses as much as digits as its factorization.

1990859813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 699840, while the sum is 53.

The square root of 1990859813 is about 44619.0521302280. The cubic root of 1990859813 is about 1257.9987996261.

The spelling of 1990859813 in words is "one billion, nine hundred ninety million, eight hundred fifty-nine thousand, eight hundred thirteen".