21086356 has 12 divisors (see below), whose sum is σ = 37137268. Its totient is φ = 10475712.

The previous prime is 21086347. The next prime is 21086381. The reversal of 21086356 is 65368012.

It can be written as a sum of positive squares in 2 ways, for example, as 10627600 + 10458756 = 3260^2 + 3234^2 .

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, 16161 + ... + 17416.

Almost surely, 2^21086356 is an apocalyptic number.

It is an amenable number.

21086356 is a deficient number, since it is larger than the sum of its proper divisors (16050912).

21086356 is a wasteful number, since it uses less digits than its factorization.

21086356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33738 (or 33736 counting only the distinct ones).

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

The square root of 21086356 is about 4591.9882404031. The cubic root of 21086356 is about 276.2700745020.

It can be divided in two parts, 2108 and 6356, that added together give a square (8464 = 92²).

The spelling of 21086356 in words is "twenty-one million, eighty-six thousand, three hundred fifty-six".