21918093 has 8 divisors (see below), whose sum is σ = 29703456. Its totient is φ = 14372400.

The previous prime is 21918079. The next prime is 21918101. The reversal of 21918093 is 39081912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21918093 - 2¹⁴ = 21901709 is a prime.

It is a super-3 number, since 3×21918093³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21918053) 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, 59703 + ... + 60068.

It is an arithmetic number, because the mean of its divisors is an integer number (3712932).

Almost surely, 2^21918093 is an apocalyptic number.

It is an amenable number.

21918093 is a deficient number, since it is larger than the sum of its proper divisors (7785363).

21918093 is a wasteful number, since it uses less digits than its factorization.

21918093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119835.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 21918093 is about 4681.6763023515. The cubic root of 21918093 is about 279.8557632970.

The spelling of 21918093 in words is "twenty-one million, nine hundred eighteen thousand, ninety-three".