21918358 has 16 divisors (see below), whose sum is σ = 40990464. Its totient is φ = 8539560.

The previous prime is 21918353. The next prime is 21918359. The reversal of 21918358 is 85381912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21918353) 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 7 ways as a sum of consecutive naturals, for example, 71010 + ... + 71317.

It is an arithmetic number, because the mean of its divisors is an integer number (2561904).

Almost surely, 2^21918358 is an apocalyptic number.

21918358 is a deficient number, since it is larger than the sum of its proper divisors (19072106).

21918358 is a wasteful number, since it uses less digits than its factorization.

21918358 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142347.

The product of its digits is 17280, while the sum is 37.

The square root of 21918358 is about 4681.7046040945. The cubic root of 21918358 is about 279.8568911548.

The spelling of 21918358 in words is "twenty-one million, nine hundred eighteen thousand, three hundred fifty-eight".