1861998 has 8 divisors (see below), whose sum is σ = 3724008. Its totient is φ = 620664.

The previous prime is 1861991. The next prime is 1862009. The reversal of 1861998 is 8991681.

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

1861998 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155161 + ... + 155172.

It is an arithmetic number, because the mean of its divisors is an integer number (465501).

2^1861998 is an apocalyptic number.

1861998 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1861998 is a wasteful number, since it uses less digits than its factorization.

1861998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310338.

The product of its digits is 31104, while the sum is 42.

The square root of 1861998 is about 1364.5504754314. The cubic root of 1861998 is about 123.0249139829.

The spelling of 1861998 in words is "one million, eight hundred sixty-one thousand, nine hundred ninety-eight".