1999998 has 128 divisors (see below), whose sum is σ = 6128640.
Its totient is φ = 466560.
The previous prime is 1999993. The next prime is 2000003. The reversal of 1999998 is 8999991.
It is an interprime number because it is at equal distance from previous prime (1999993) and next prime (2000003).
It is a Harshad number since it is a multiple of its sum of digits (54).
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1999993) by changing a digit.
It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 54036 + ... + 54072.
It is an arithmetic number, because the mean of its divisors is an integer number (47880).
21999998 is an apocalyptic number.
1999998 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 1999998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3064320).
1999998 is an abundant number, since it is smaller than the sum of its proper divisors (4128642).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1999998 is a wasteful number, since it uses less digits than its factorization.
1999998 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 79 (or 73 counting only the distinct ones).
The product of its digits is 472392, while the sum is 54.
The square root of 1999998 is about 1414.2128552661.
The cubic root of 1999998 is about 125.9920629921.
It can be divided in two parts, 1 and 999998, that added together give a palindrome (999999).
The spelling of 1999998 in words is "one million, nine hundred ninety-nine thousand, nine hundred ninety-eight".