20115866 has 4 divisors (see below), whose sum is σ = 30173802. Its totient is φ = 10057932.

The previous prime is 20115853. The next prime is 20115883. The reversal of 20115866 is 66851102.

It is a happy number.

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., 19989841 + 126025 = 4471^2 + 355^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5028965 + ... + 5028968.

Almost surely, 2^20115866 is an apocalyptic number.

20115866 is a deficient number, since it is larger than the sum of its proper divisors (10057936).

20115866 is a wasteful number, since it uses less digits than its factorization.

20115866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10057935.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 20115866 is about 4485.0714598543. The cubic root of 20115866 is about 271.9649338445.

Adding to 20115866 its reverse (66851102), we get a palindrome (86966968).

The spelling of 20115866 in words is "twenty million, one hundred fifteen thousand, eight hundred sixty-six".