2181965986 has 4 divisors (see below), whose sum is σ = 3272948982. Its totient is φ = 1090982992.

The previous prime is 2181965977. The next prime is 2181965987. The reversal of 2181965986 is 6895691812.

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

It can be written as a sum of positive squares in only one way, i.e., 1804635361 + 377330625 = 42481^2 + 19425^2 .

It is not an unprimeable number, because it can be changed into a prime (2181965987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545491495 + ... + 545491498.

Almost surely, 2^2181965986 is an apocalyptic number.

2181965986 is a deficient number, since it is larger than the sum of its proper divisors (1090982996).

2181965986 is a wasteful number, since it uses less digits than its factorization.

2181965986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090982995.

The product of its digits is 1866240, while the sum is 55.

The square root of 2181965986 is about 46711.5187721401. The cubic root of 2181965986 is about 1297.0279216131.

The spelling of 2181965986 in words is "two billion, one hundred eighty-one million, nine hundred sixty-five thousand, nine hundred eighty-six".