21086361 has 12 divisors (see below), whose sum is σ = 30888000. Its totient is φ = 13859160.

The previous prime is 21086347. The next prime is 21086381. The reversal of 21086361 is 16368012.

21086361 is a `hidden beast` number, since 21 + 0 + 8 + 636 + 1 = 666.

It is not a de Polignac number, because 21086361 - 2¹¹ = 21084313 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21086311) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15861 + ... + 17138.

It is an arithmetic number, because the mean of its divisors is an integer number (2574000).

Almost surely, 2^21086361 is an apocalyptic number.

It is an amenable number.

21086361 is a deficient number, since it is larger than the sum of its proper divisors (9801639).

21086361 is a wasteful number, since it uses less digits than its factorization.

21086361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33076 (or 33073 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21086361 is about 4591.9887848295. The cubic root of 21086361 is about 276.2700963384.

The spelling of 21086361 in words is "twenty-one million, eighty-six thousand, three hundred sixty-one".