21982772 has 36 divisors (see below), whose sum is σ = 47113920. Its totient is φ = 8923824.

The previous prime is 21982769. The next prime is 21982781. The reversal of 21982772 is 27728912.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 773 + ... + 6675.

It is an arithmetic number, because the mean of its divisors is an integer number (1308720).

Almost surely, 2^21982772 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 21982772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23556960).

21982772 is an abundant number, since it is smaller than the sum of its proper divisors (25131148).

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

21982772 is a wasteful number, since it uses less digits than its factorization.

21982772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5940 (or 5931 counting only the distinct ones).

The product of its digits is 28224, while the sum is 38.

The square root of 21982772 is about 4688.5788891731. The cubic root of 21982772 is about 280.1307722475.

The spelling of 21982772 in words is "twenty-one million, nine hundred eighty-two thousand, seven hundred seventy-two".