1998757331 has 2 divisors, whose sum is σ = 1998757332. Its totient is φ = 1998757330.

The previous prime is 1998757273. The next prime is 1998757357. The reversal of 1998757331 is 1337578991.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1998757331 is a prime.

It is a super-2 number, since 2×1998757331² = 7990061736452487122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1998757381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999378665 + 999378666.

It is an arithmetic number, because the mean of its divisors is an integer number (999378666).

Almost surely, 2^1998757331 is an apocalyptic number.

1998757331 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998757331 is an equidigital number, since it uses as much as digits as its factorization.

1998757331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1428840, while the sum is 53.

The square root of 1998757331 is about 44707.4639294156. The cubic root of 1998757331 is about 1259.6600516932.

The spelling of 1998757331 in words is "one billion, nine hundred ninety-eight million, seven hundred fifty-seven thousand, three hundred thirty-one".