21206712 has 16 divisors (see below), whose sum is σ = 53016840. Its totient is φ = 7068896.

The previous prime is 21206699. The next prime is 21206747. The reversal of 21206712 is 21760212.

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, 441783 + ... + 441830.

Almost surely, 2^21206712 is an apocalyptic number.

It is an amenable number.

21206712 is an abundant number, since it is smaller than the sum of its proper divisors (31810128).

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

21206712 is a wasteful number, since it uses less digits than its factorization.

21206712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883622 (or 883618 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21206712 is about 4605.0745922298. The cubic root of 21206712 is about 276.7947059809.

Adding to 21206712 its reverse (21760212), we get a palindrome (42966924).

The spelling of 21206712 in words is "twenty-one million, two hundred six thousand, seven hundred twelve".