21810086 has 4 divisors (see below), whose sum is σ = 32715132. Its totient is φ = 10905042.

The previous prime is 21810079. The next prime is 21810109. The reversal of 21810086 is 68001812.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5452520 + ... + 5452523.

It is an arithmetic number, because the mean of its divisors is an integer number (8178783).

Almost surely, 2^21810086 is an apocalyptic number.

21810086 is a deficient number, since it is larger than the sum of its proper divisors (10905046).

21810086 is a wasteful number, since it uses less digits than its factorization.

21810086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10905045.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 21810086 is about 4670.1269790017. The cubic root of 21810086 is about 279.3953192367.

Adding to 21810086 its reverse (68001812), we get a palindrome (89811898).

The spelling of 21810086 in words is "twenty-one million, eight hundred ten thousand, eighty-six".