2155986 has 48 divisors (see below), whose sum is σ = 5436288. Its totient is φ = 604800.

The previous prime is 2155963. The next prime is 2155999. The reversal of 2155986 is 6895512.

It is a happy number.

2155986 is a `hidden beast` number, since 21 + 559 + 86 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 2155986.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8826 + ... + 9066.

It is an arithmetic number, because the mean of its divisors is an integer number (113256).

2^2155986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2155986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2718144).

2155986 is an abundant number, since it is smaller than the sum of its proper divisors (3280302).

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

2155986 is a wasteful number, since it uses less digits than its factorization.

2155986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 324 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 2155986 is about 1468.3276201175. The cubic root of 2155986 is about 129.1859585938.

The spelling of 2155986 in words is "two million, one hundred fifty-five thousand, nine hundred eighty-six".