1998403628731 has 2 divisors, whose sum is σ = 1998403628732. Its totient is φ = 1998403628730.

The previous prime is 1998403628723. The next prime is 1998403628777. The reversal of 1998403628731 is 1378263048991.

It is a weak prime.

It is an emirp because it is prime and its reverse (1378263048991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1998403628731 - 2³ = 1998403628723 is a prime.

It is a super-3 number, since 3×1998403628731³ (a number of 38 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 1998403628731.

It is not a weakly prime, because it can be changed into another prime (1998403628131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999201814365 + 999201814366.

It is an arithmetic number, because the mean of its divisors is an integer number (999201814366).

Almost surely, 2^{1998403628731} is an apocalyptic number.

1998403628731 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998403628731 is an equidigital number, since it uses as much as digits as its factorization.

1998403628731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15676416, while the sum is 61.

The spelling of 1998403628731 in words is "one trillion, nine hundred ninety-eight billion, four hundred three million, six hundred twenty-eight thousand, seven hundred thirty-one".