1998761 has 2 divisors, whose sum is σ = 1998762. Its totient is φ = 1998760.

The previous prime is 1998739. The next prime is 1998793. The reversal of 1998761 is 1678991.

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., 1038361 + 960400 = 1019^2 + 980^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998761 - 2⁶ = 1998697 is a prime.

It is not a weakly prime, because it can be changed into another prime (1998701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999380 + 999381.

It is an arithmetic number, because the mean of its divisors is an integer number (999381).

2^1998761 is an apocalyptic number.

It is an amenable number.

1998761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998761 is an equidigital number, since it uses as much as digits as its factorization.

1998761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 41.

The square root of 1998761 is about 1413.7754418577. The cubic root of 1998761 is about 125.9660822454.

The spelling of 1998761 in words is "one million, nine hundred ninety-eight thousand, seven hundred sixty-one".