1998613 has 4 divisors (see below), whose sum is σ = 2007148. Its totient is φ = 1990080.

The previous prime is 1998611. The next prime is 1998617. The reversal of 1998613 is 3168991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 964324 + 1034289 = 982^2 + 1017^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998613 - 2¹ = 1998611 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3906 + ... + 4387.

It is an arithmetic number, because the mean of its divisors is an integer number (501787).

2^1998613 is an apocalyptic number.

It is an amenable number.

1998613 is a deficient number, since it is larger than the sum of its proper divisors (8535).

1998613 is an equidigital number, since it uses as much as digits as its factorization.

1998613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8534.

The product of its digits is 11664, while the sum is 37.

The square root of 1998613 is about 1413.7230987715. The cubic root of 1998613 is about 125.9629730792.

The spelling of 1998613 in words is "one million, nine hundred ninety-eight thousand, six hundred thirteen".