2181163988 has 12 divisors (see below), whose sum is σ = 4041568692. Its totient is φ = 1026430080.

The previous prime is 2181163987. The next prime is 2181164021. The reversal of 2181163988 is 8893611812.

It can be written as a sum of positive squares in 2 ways, for example, as 1248350224 + 932813764 = 35332^2 + 30542^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181163987) 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, 16037903 + ... + 16038038.

It is an arithmetic number, because the mean of its divisors is an integer number (336797391).

Almost surely, 2^2181163988 is an apocalyptic number.

It is an amenable number.

2181163988 is a deficient number, since it is larger than the sum of its proper divisors (1860404704).

2181163988 is a wasteful number, since it uses less digits than its factorization.

2181163988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32075962 (or 32075960 counting only the distinct ones).

The product of its digits is 165888, while the sum is 47.

The square root of 2181163988 is about 46702.9333982353. The cubic root of 2181163988 is about 1296.8689913520.

The spelling of 2181163988 in words is "two billion, one hundred eighty-one million, one hundred sixty-three thousand, nine hundred eighty-eight".