1998860 has 24 divisors (see below), whose sum is σ = 4445280. Its totient is φ = 752384.

The previous prime is 1998839. The next prime is 1998881. The reversal of 1998860 is 688991.

1998860 = T₂₅ + T₂₆ + ... + T₂₂₈.

It is an interprime number because it is at equal distance from previous prime (1998839) and next prime (1998881).

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2600 + ... + 3279.

It is an arithmetic number, because the mean of its divisors is an integer number (185220).

2^1998860 is an apocalyptic number.

1998860 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1998860 is an abundant number, since it is smaller than the sum of its proper divisors (2446420).

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

1998860 is a wasteful number, since it uses less digits than its factorization.

1998860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5905 (or 5903 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1998860 is about 1413.8104540567. The cubic root of 1998860 is about 125.9681619398.

The spelling of 1998860 in words is "one million, nine hundred ninety-eight thousand, eight hundred sixty".