21756672 has 216 divisors, whose sum is σ = 76527360. Its totient is φ = 5806080.

The previous prime is 21756671. The next prime is 21756677. The reversal of 21756672 is 27665712.

21756672 is a `hidden beast` number, since 21 + 7 + 566 + 72 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (21756671) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 306397 + ... + 306467.

Almost surely, 2^21756672 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 21756672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38263680).

21756672 is an abundant number, since it is smaller than the sum of its proper divisors (54770688).

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

21756672 is a wasteful number, since it uses less digits than its factorization.

21756672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 102 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 21756672 is about 4664.4047851789. The cubic root of 21756672 is about 279.1670483795.

The spelling of 21756672 in words is "twenty-one million, seven hundred fifty-six thousand, six hundred seventy-two".