1990813 has 6 divisors (see below), whose sum is σ = 2188382. Its totient is φ = 1809720.

The previous prime is 1990787. The next prime is 1990823. The reversal of 1990813 is 3180991.

It can be written as a sum of positive squares in only one way, i.e., 1951609 + 39204 = 1397^2 + 198^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1990813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8106 + ... + 8347.

2^1990813 is an apocalyptic number.

It is an amenable number.

1990813 is a deficient number, since it is larger than the sum of its proper divisors (197569).

1990813 is a wasteful number, since it uses less digits than its factorization.

1990813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16475 (or 16464 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 1990813 is about 1410.9617287510. The cubic root of 1990813 is about 125.7988939371.

The spelling of 1990813 in words is "one million, nine hundred ninety thousand, eight hundred thirteen".