1998581 has 8 divisors (see below), whose sum is σ = 2198784. Its totient is φ = 1805040.

The previous prime is 1998569. The next prime is 1998587. The reversal of 1998581 is 1858991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1998581 - 2⁶ = 1998517 is a prime.

It is a super-2 number, since 2×1998581² = 7988652027122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998587) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1025 + ... + 2246.

It is an arithmetic number, because the mean of its divisors is an integer number (274848).

2^1998581 is an apocalyptic number.

It is an amenable number.

1998581 is a deficient number, since it is larger than the sum of its proper divisors (200203).

1998581 is a wasteful number, since it uses less digits than its factorization.

1998581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3331.

The product of its digits is 25920, while the sum is 41.

The square root of 1998581 is about 1413.7117810926. The cubic root of 1998581 is about 125.9623008069.

The spelling of 1998581 in words is "one million, nine hundred ninety-eight thousand, five hundred eighty-one".