1998738 has 48 divisors (see below), whose sum is σ = 5129280. Its totient is φ = 550368.

The previous prime is 1998727. The next prime is 1998739. The reversal of 1998738 is 8378991.

It is a junction number, because it is equal to n+sod(n) for n = 1998693 and 1998702.

It is not an unprimeable number, because it can be changed into a prime (1998739) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3381 + ... + 3927.

It is an arithmetic number, because the mean of its divisors is an integer number (106860).

2^1998738 is an apocalyptic number.

1998738 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2564640).

1998738 is an abundant number, since it is smaller than the sum of its proper divisors (3130542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1998738 is a wasteful number, since it uses less digits than its factorization.

1998738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 591 (or 588 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 1998738 is about 1413.7673075864. The cubic root of 1998738 is about 125.9655990742.

The spelling of 1998738 in words is "one million, nine hundred ninety-eight thousand, seven hundred thirty-eight".