21772284 has 12 divisors (see below), whose sum is σ = 50802024. Its totient is φ = 7257424.

The previous prime is 21772259. The next prime is 21772313. The reversal of 21772284 is 48227712.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 907167 + ... + 907190.

It is an arithmetic number, because the mean of its divisors is an integer number (4233502).

Almost surely, 2^21772284 is an apocalyptic number.

It is an amenable number.

21772284 is an abundant number, since it is smaller than the sum of its proper divisors (29029740).

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

21772284 is a wasteful number, since it uses less digits than its factorization.

21772284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1814364 (or 1814362 counting only the distinct ones).

The product of its digits is 12544, while the sum is 33.

The square root of 21772284 is about 4666.0780104923. The cubic root of 21772284 is about 279.2338066578.

Adding to 21772284 its reverse (48227712), we get a palindrome (69999996).

The spelling of 21772284 in words is "twenty-one million, seven hundred seventy-two thousand, two hundred eighty-four".