21896660 has 12 divisors (see below), whose sum is σ = 45983028. Its totient is φ = 8758656.

The previous prime is 21896639. The next prime is 21896669. The reversal of 21896660 is 6669812.

It can be written as a sum of positive squares in 2 ways, for example, as 8690704 + 13205956 = 2948^2 + 3634^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21896669) 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 3 ways as a sum of consecutive naturals, for example, 547397 + ... + 547436.

It is an arithmetic number, because the mean of its divisors is an integer number (3831919).

Almost surely, 2^21896660 is an apocalyptic number.

21896660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21896660 is an abundant number, since it is smaller than the sum of its proper divisors (24086368).

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

21896660 is a wasteful number, since it uses less digits than its factorization.

21896660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1094842 (or 1094840 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 21896660 is about 4679.3867119528. The cubic root of 21896660 is about 279.7645128892.

The spelling of 21896660 in words is "twenty-one million, eight hundred ninety-six thousand, six hundred sixty".