21084312 has 16 divisors (see below), whose sum is σ = 52710840. Its totient is φ = 7028096.

The previous prime is 21084311. The next prime is 21084313. The reversal of 21084312 is 21348012.

It is an interprime number because it is at equal distance from previous prime (21084311) and next prime (21084313).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21084311) 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, 439233 + ... + 439280.

Almost surely, 2^21084312 is an apocalyptic number.

It is an amenable number.

21084312 is an abundant number, since it is smaller than the sum of its proper divisors (31626528).

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

21084312 is a wasteful number, since it uses less digits than its factorization.

21084312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878522 (or 878518 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21084312 is about 4591.7656734637. The cubic root of 21084312 is about 276.2611474928.

The spelling of 21084312 in words is "twenty-one million, eighty-four thousand, three hundred twelve".