21288996 has 27 divisors (see below), whose sum is σ = 53883921. Its totient is φ = 7087104.

The previous prime is 21288991. The next prime is 21288997. The reversal of 21288996 is 69988212.

The square root of 21288996 is 4614.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 8328996 + 12960000 = 2886^2 + 3600^2 .

It is not an unprimeable number, because it can be changed into a prime (21288991) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 27300 + ... + 28068.

Almost surely, 2^21288996 is an apocalyptic number.

21288996 is the 4614-th square number.

It is an amenable number.

21288996 is an abundant number, since it is smaller than the sum of its proper divisors (32594925).

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

21288996 is an equidigital number, since it uses as much as digits as its factorization.

21288996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1548 (or 774 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The cubic root of 21288996 is about 277.1522402929.

The spelling of 21288996 in words is "twenty-one million, two hundred eighty-eight thousand, nine hundred ninety-six".