1998987593 has 2 divisors, whose sum is σ = 1998987594. Its totient is φ = 1998987592.

The previous prime is 1998987563. The next prime is 1998987647. The reversal of 1998987593 is 3957898991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1998805264 + 182329 = 44708^2 + 427^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998987593 - 2⁸ = 1998987337 is a prime.

It is not a weakly prime, because it can be changed into another prime (1998987563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999493796 + 999493797.

It is an arithmetic number, because the mean of its divisors is an integer number (999493797).

Almost surely, 2^1998987593 is an apocalyptic number.

It is an amenable number.

1998987593 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998987593 is an equidigital number, since it uses as much as digits as its factorization.

1998987593 is an evil number, because the sum of its binary digits is even.

The product of its digits is 44089920, while the sum is 68.

The square root of 1998987593 is about 44710.0390628324. The cubic root of 1998987593 is about 1259.7084218648.

The spelling of 1998987593 in words is "one billion, nine hundred ninety-eight million, nine hundred eighty-seven thousand, five hundred ninety-three".