218011990 has 32 divisors (see below), whose sum is σ = 452612160. Its totient is φ = 74058624.

The previous prime is 218011979. The next prime is 218011999. The reversal of 218011990 is 99110812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218011999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6657 + ... + 21916.

It is an arithmetic number, because the mean of its divisors is an integer number (14144130).

Almost surely, 2^218011990 is an apocalyptic number.

218011990 is an abundant number, since it is smaller than the sum of its proper divisors (234600170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218011990 is a wasteful number, since it uses less digits than its factorization.

218011990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28696.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 218011990 is about 14765.2290872848. The cubic root of 218011990 is about 601.8571991247.

The spelling of 218011990 in words is "two hundred eighteen million, eleven thousand, nine hundred ninety".