1986864 has 80 divisors (see below), whose sum is σ = 5785344. Its totient is φ = 582400.

The previous prime is 1986839. The next prime is 1986869. The reversal of 1986864 is 4686891.

It is not an unprimeable number, because it can be changed into a prime (1986869) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27949 + ... + 28019.

2^1986864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1986864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2892672).

1986864 is an abundant number, since it is smaller than the sum of its proper divisors (3798480).

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

1986864 is a wasteful number, since it uses less digits than its factorization.

1986864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 140 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 1986864 is about 1409.5616339841. The cubic root of 1986864 is about 125.7156601581.

It can be divided in two parts, 1986 and 864, that added together give a triangular number (2850 = T₇₅).

The spelling of 1986864 in words is "one million, nine hundred eighty-six thousand, eight hundred sixty-four".