21170086 has 16 divisors (see below), whose sum is σ = 37463040. Its totient is φ = 8780040.

The previous prime is 21170077. The next prime is 21170099. The reversal of 21170086 is 68007112.

It is a self number, because there is not a number n which added to its sum of digits gives 21170086.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23956 + ... + 24823.

It is an arithmetic number, because the mean of its divisors is an integer number (2341440).

Almost surely, 2^21170086 is an apocalyptic number.

21170086 is a deficient number, since it is larger than the sum of its proper divisors (16292954).

21170086 is a wasteful number, since it uses less digits than its factorization.

21170086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48819.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 21170086 is about 4601.0961737395. The cubic root of 21170086 is about 276.6352639315.

Adding to 21170086 its reverse (68007112), we get a palindrome (89177198).

The spelling of 21170086 in words is "twenty-one million, one hundred seventy thousand, eighty-six".