21966672 has 160 divisors (see below), whose sum is σ = 71995392. Its totient is φ = 5617152.

The previous prime is 21966667. The next prime is 21966677. The reversal of 21966672 is 27666912.

It is an interprime number because it is at equal distance from previous prime (21966667) and next prime (21966677).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 21966672.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21966677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 205243 + ... + 205349.

Almost surely, 2^21966672 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 21966672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35997696).

21966672 is an abundant number, since it is smaller than the sum of its proper divisors (50028720).

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

21966672 is a wasteful number, since it uses less digits than its factorization.

21966672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185 (or 179 counting only the distinct ones).

The product of its digits is 54432, while the sum is 39.

The square root of 21966672 is about 4686.8616365325. The cubic root of 21966672 is about 280.0623670597.

The spelling of 21966672 in words is "twenty-one million, nine hundred sixty-six thousand, six hundred seventy-two".