18866850021 has 32 divisors (see below), whose sum is σ = 29660544000. Its totient is φ = 11827095984.

The previous prime is 18866850017. The next prime is 18866850043. The reversal of 18866850021 is 12005866881.

18866850021 is a `hidden beast` number, since 1 + 8 + 86 + 68 + 500 + 2 + 1 = 666.

It is not a de Polignac number, because 18866850021 - 2² = 18866850017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18866850001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 220831 + ... + 294108.

It is an arithmetic number, because the mean of its divisors is an integer number (926892000).

Almost surely, 2^18866850021 is an apocalyptic number.

It is an amenable number.

18866850021 is a deficient number, since it is larger than the sum of its proper divisors (10793693979).

18866850021 is a wasteful number, since it uses less digits than its factorization.

18866850021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515030 (or 515024 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 18866850021 in words is "eighteen billion, eight hundred sixty-six million, eight hundred fifty thousand, twenty-one".