21086312 has 16 divisors (see below), whose sum is σ = 42578340. Its totient is φ = 9732096.

The previous prime is 21086311. The next prime is 21086321. The reversal of 21086312 is 21368012.

It can be written as a sum of positive squares in 2 ways, for example, as 20921476 + 164836 = 4574^2 + 406^2 .

It is a super-2 number, since 2×21086312² = 889265107522688, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 101273 + ... + 101480.

Almost surely, 2^21086312 is an apocalyptic number.

It is an amenable number.

21086312 is an abundant number, since it is smaller than the sum of its proper divisors (21492028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21086312 is a wasteful number, since it uses less digits than its factorization.

21086312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202772 (or 202768 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21086312 is about 4591.9834494475. The cubic root of 21086312 is about 276.2698823415.

The spelling of 21086312 in words is "twenty-one million, eighty-six thousand, three hundred twelve".