21570972 has 12 divisors (see below), whose sum is σ = 50332296. Its totient is φ = 7190320.

The previous prime is 21570929. The next prime is 21571001. The reversal of 21570972 is 27907512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 898779 + ... + 898802.

It is an arithmetic number, because the mean of its divisors is an integer number (4194358).

Almost surely, 2^21570972 is an apocalyptic number.

It is an amenable number.

21570972 is an abundant number, since it is smaller than the sum of its proper divisors (28761324).

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

21570972 is a wasteful number, since it uses less digits than its factorization.

21570972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1797588 (or 1797586 counting only the distinct ones).

The product of its (nonzero) digits is 8820, while the sum is 33.

The square root of 21570972 is about 4644.4560499589. The cubic root of 21570972 is about 278.3705184959.

The spelling of 21570972 in words is "twenty-one million, five hundred seventy thousand, nine hundred seventy-two".