2188645987 has 4 divisors (see below), whose sum is σ = 2387613816. Its totient is φ = 1989678160.

The previous prime is 2188645981. The next prime is 2188645997. The reversal of 2188645987 is 7895468812.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2188645987 - 2¹¹ = 2188643939 is a prime.

It is a super-2 number, since 2×2188645987² = 9580342512822408338, which contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2188645981) 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 3 ways as a sum of consecutive naturals, for example, 99483898 + ... + 99483919.

It is an arithmetic number, because the mean of its divisors is an integer number (596903454).

Almost surely, 2^2188645987 is an apocalyptic number.

2188645987 is a deficient number, since it is larger than the sum of its proper divisors (198967829).

2188645987 is a wasteful number, since it uses less digits than its factorization.

2188645987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198967828.

The product of its digits is 7741440, while the sum is 58.

The square root of 2188645987 is about 46782.9668469198. The cubic root of 2188645987 is about 1298.3501727740.

The spelling of 2188645987 in words is "two billion, one hundred eighty-eight million, six hundred forty-five thousand, nine hundred eighty-seven".