21966280 has 64 divisors (see below), whose sum is σ = 59472000. Its totient is φ = 7133184.

The previous prime is 21966257. The next prime is 21966281. The reversal of 21966280 is 8266912.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21966281) 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 15 ways as a sum of consecutive naturals, for example, 3256 + ... + 7384.

It is an arithmetic number, because the mean of its divisors is an integer number (929250).

Almost surely, 2^21966280 is an apocalyptic number.

21966280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21966280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29736000).

21966280 is an abundant number, since it is smaller than the sum of its proper divisors (37505720).

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

21966280 is a wasteful number, since it uses less digits than its factorization.

21966280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4166 (or 4162 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 21966280 is about 4686.8198173175. The cubic root of 21966280 is about 280.0607011254.

Subtracting from 21966280 its product of nonzero digits (10368), we obtain a palindrome (21955912).

The spelling of 21966280 in words is "twenty-one million, nine hundred sixty-six thousand, two hundred eighty".