21439086 has 8 divisors (see below), whose sum is σ = 42878184. Its totient is φ = 7146360.

The previous prime is 21439079. The next prime is 21439109. The reversal of 21439086 is 68093412.

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

21439086 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 11.

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, 1786585 + ... + 1786596.

It is an arithmetic number, because the mean of its divisors is an integer number (5359773).

Almost surely, 2^21439086 is an apocalyptic number.

21439086 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21439086 is a wasteful number, since it uses less digits than its factorization.

21439086 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3573186.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21439086 is about 4630.2360630966. The cubic root of 21439086 is about 277.8020345869.

The spelling of 21439086 in words is "twenty-one million, four hundred thirty-nine thousand, eighty-six".