1998731129 has 2 divisors, whose sum is σ = 1998731130. Its totient is φ = 1998731128.

The previous prime is 1998731113. The next prime is 1998731143. The reversal of 1998731129 is 9211378991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1652585104 + 346146025 = 40652^2 + 18605^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998731129 - 2⁴ = 1998731113 is a prime.

It is a super-2 number, since 2×1998731129² = 7989852252067229282, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1998731629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999365564 + 999365565.

It is an arithmetic number, because the mean of its divisors is an integer number (999365565).

Almost surely, 2^1998731129 is an apocalyptic number.

It is an amenable number.

1998731129 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998731129 is an equidigital number, since it uses as much as digits as its factorization.

1998731129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 50.

The square root of 1998731129 is about 44707.1708901380. The cubic root of 1998731129 is about 1259.6545473136.

The spelling of 1998731129 in words is "one billion, nine hundred ninety-eight million, seven hundred thirty-one thousand, one hundred twenty-nine".