21571712 has 32 divisors (see below), whose sum is σ = 43345920. Its totient is φ = 10692864.

The previous prime is 21571673. The next prime is 21571721. The reversal of 21571712 is 21717512.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×21571712² = 930677517221888, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 15593 + ... + 16919.

It is an arithmetic number, because the mean of its divisors is an integer number (1354560).

Almost surely, 2^21571712 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 21571712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21672960).

21571712 is an abundant number, since it is smaller than the sum of its proper divisors (21774208).

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

21571712 is a wasteful number, since it uses less digits than its factorization.

21571712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1468 (or 1456 counting only the distinct ones).

The product of its digits is 980, while the sum is 26.

The square root of 21571712 is about 4644.5357141484. The cubic root of 21571712 is about 278.3737016600.

The spelling of 21571712 in words is "twenty-one million, five hundred seventy-one thousand, seven hundred twelve".