1998420 has 48 divisors (see below), whose sum is σ = 5893440. Its totient is φ = 504576.

The previous prime is 1998413. The next prime is 1998427. The reversal of 1998420 is 248991.

1998420 = T₄₃₇ + T₄₃₈ + ... + T₄₅₆.

It is an interprime number because it is at equal distance from previous prime (1998413) and next prime (1998427).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 264 + ... + 2016.

It is an arithmetic number, because the mean of its divisors is an integer number (122780).

2^1998420 is an apocalyptic number.

1998420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1998420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2946720).

1998420 is an abundant number, since it is smaller than the sum of its proper divisors (3895020).

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

1998420 is a wasteful number, since it uses less digits than its factorization.

1998420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1784 (or 1782 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 1998420 is about 1413.6548376460. The cubic root of 1998420 is about 125.9589183278.

It can be divided in two parts, 1998 and 420, that multiplied together give a triangular number (839160 = T₁₂₉₅).

The spelling of 1998420 in words is "one million, nine hundred ninety-eight thousand, four hundred twenty".