218833021 has 4 divisors (see below), whose sum is σ = 238726944. Its totient is φ = 198939100.

The previous prime is 218833019. The next prime is 218833057. The reversal of 218833021 is 120338812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 218833021 - 2¹ = 218833019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218833001) 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, 9946945 + ... + 9946966.

It is an arithmetic number, because the mean of its divisors is an integer number (59681736).

Almost surely, 2^218833021 is an apocalyptic number.

It is an amenable number.

218833021 is a deficient number, since it is larger than the sum of its proper divisors (19893923).

218833021 is a wasteful number, since it uses less digits than its factorization.

218833021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19893922.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 218833021 is about 14793.0058135593. The cubic root of 218833021 is about 602.6117820868.

The spelling of 218833021 in words is "two hundred eighteen million, eight hundred thirty-three thousand, twenty-one".