21918086 has 8 divisors (see below), whose sum is σ = 32920104. Its totient is φ = 10944720.

The previous prime is 21918079. The next prime is 21918101. The reversal of 21918086 is 68081912.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5135 + ... + 8378.

It is an arithmetic number, because the mean of its divisors is an integer number (4115013).

Almost surely, 2^21918086 is an apocalyptic number.

21918086 is a deficient number, since it is larger than the sum of its proper divisors (11002018).

21918086 is a wasteful number, since it uses less digits than its factorization.

21918086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14326.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 21918086 is about 4681.6755547560. The cubic root of 21918086 is about 279.8557335044.

Adding to 21918086 its reverse (68081912), we get a palindrome (89999998).

The spelling of 21918086 in words is "twenty-one million, nine hundred eighteen thousand, eighty-six".