21089772 has 72 divisors (see below), whose sum is σ = 61239360. Its totient is φ = 6052320.

The previous prime is 21089771. The next prime is 21089777. The reversal of 21089772 is 27798012.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21089771) 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 23 ways as a sum of consecutive naturals, for example, 6123 + ... + 8925.

Almost surely, 2^21089772 is an apocalyptic number.

21089772 is a gapful number since it is divisible by the number (22) 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 21089772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30619680).

21089772 is an abundant number, since it is smaller than the sum of its proper divisors (40149588).

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

21089772 is a wasteful number, since it uses less digits than its factorization.

21089772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2843 (or 2838 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21089772 is about 4592.3601775122. The cubic root of 21089772 is about 276.2849923256.

The spelling of 21089772 in words is "twenty-one million, eighty-nine thousand, seven hundred seventy-two".