21286616 has 16 divisors (see below), whose sum is σ = 42982800. Its totient is φ = 9824544.

The previous prime is 21286613. The next prime is 21286627. The reversal of 21286616 is 61668212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21286613) 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, 102236 + ... + 102443.

It is an arithmetic number, because the mean of its divisors is an integer number (2686425).

Almost surely, 2^21286616 is an apocalyptic number.

21286616 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21286616 is an abundant number, since it is smaller than the sum of its proper divisors (21696184).

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

21286616 is a wasteful number, since it uses less digits than its factorization.

21286616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204698 (or 204694 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 21286616 is about 4613.7420820848. The cubic root of 21286616 is about 277.1419118441.

The spelling of 21286616 in words is "twenty-one million, two hundred eighty-six thousand, six hundred sixteen".