1998213523 has 2 divisors, whose sum is σ = 1998213524. Its totient is φ = 1998213522.

The previous prime is 1998213509. The next prime is 1998213557. The reversal of 1998213523 is 3253128991.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1998213523 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1998213523.

It is not a weakly prime, because it can be changed into another prime (1998213323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999106761 + 999106762.

It is an arithmetic number, because the mean of its divisors is an integer number (999106762).

Almost surely, 2^1998213523 is an apocalyptic number.

1998213523 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998213523 is an equidigital number, since it uses as much as digits as its factorization.

1998213523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 43.

The square root of 1998213523 is about 44701.3816676845. The cubic root of 1998213523 is about 1259.5458014810.

The spelling of 1998213523 in words is "one billion, nine hundred ninety-eight million, two hundred thirteen thousand, five hundred twenty-three".