21086365 has 8 divisors (see below), whose sum is σ = 25528248. Its totient is φ = 16719360.

The previous prime is 21086347. The next prime is 21086381. The reversal of 21086365 is 56368012.

It can be written as a sum of positive squares in 4 ways, for example, as 674041 + 20412324 = 821^2 + 4518^2 .

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

It is not a de Polignac number, because 21086365 - 2⁷ = 21086237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18096 + ... + 19225.

It is an arithmetic number, because the mean of its divisors is an integer number (3191031).

Almost surely, 2^21086365 is an apocalyptic number.

It is an amenable number.

21086365 is a deficient number, since it is larger than the sum of its proper divisors (4441883).

21086365 is a wasteful number, since it uses less digits than its factorization.

21086365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37439.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 21086365 is about 4591.9892203706. The cubic root of 21086365 is about 276.2701138075.

The spelling of 21086365 in words is "twenty-one million, eighty-six thousand, three hundred sixty-five".