1990334581 has 2 divisors, whose sum is σ = 1990334582. Its totient is φ = 1990334580.

The previous prime is 1990334527. The next prime is 1990334597. The reversal of 1990334581 is 1854330991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1257766225 + 732568356 = 35465^2 + 27066^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990334581 - 2¹³ = 1990326389 is a prime.

It is a super-2 number, since 2×1990334581² = 7922863488648891122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1990334681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995167290 + 995167291.

It is an arithmetic number, because the mean of its divisors is an integer number (995167291).

Almost surely, 2^1990334581 is an apocalyptic number.

It is an amenable number.

1990334581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990334581 is an equidigital number, since it uses as much as digits as its factorization.

1990334581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 1990334581 is about 44613.1660051156. The cubic root of 1990334581 is about 1257.8881607729. Note that the first 3 decimals are identical.

The spelling of 1990334581 in words is "one billion, nine hundred ninety million, three hundred thirty-four thousand, five hundred eighty-one".