21059712 has 96 divisors (see below), whose sum is σ = 61539660. Its totient is φ = 6912000.

The previous prime is 21059711. The next prime is 21059729. The reversal of 21059712 is 21795012.

It can be written as a sum of positive squares in 2 ways, for example, as 21013056 + 46656 = 4584^2 + 216^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×21059712² = 887022939045888, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21059711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116262 + ... + 116442.

Almost surely, 2^21059712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21059712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30769830).

21059712 is an abundant number, since it is smaller than the sum of its proper divisors (40479948).

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

21059712 is a wasteful number, since it uses less digits than its factorization.

21059712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21059712 is about 4589.0861835446. The cubic root of 21059712 is about 276.1536636439.

The spelling of 21059712 in words is "twenty-one million, fifty-nine thousand, seven hundred twelve".