1990013261 has 2 divisors, whose sum is σ = 1990013262. Its totient is φ = 1990013260.

The previous prime is 1990013257. The next prime is 1990013303. The reversal of 1990013261 is 1623100991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1969673161 + 20340100 = 44381^2 + 4510^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990013261 - 2² = 1990013257 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1990013461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995006630 + 995006631.

It is an arithmetic number, because the mean of its divisors is an integer number (995006631).

Almost surely, 2^1990013261 is an apocalyptic number.

It is an amenable number.

1990013261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990013261 is an equidigital number, since it uses as much as digits as its factorization.

1990013261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1990013261 is about 44609.5646806825. The cubic root of 1990013261 is about 1257.8204658938.

The spelling of 1990013261 in words is "one billion, nine hundred ninety million, thirteen thousand, two hundred sixty-one".