21641288 has 16 divisors (see below), whose sum is σ = 41134380. Its totient is φ = 10672128.

The previous prime is 21641281. The next prime is 21641303. The reversal of 21641288 is 88214612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19731364 + 1909924 = 4442^2 + 1382^2 .

It is not an unprimeable number, because it can be changed into a prime (21641281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17945 + ... + 19112.

Almost surely, 2^21641288 is an apocalyptic number.

It is an amenable number.

21641288 is a deficient number, since it is larger than the sum of its proper divisors (19493092).

21641288 is a wasteful number, since it uses less digits than its factorization.

21641288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37136 (or 37132 counting only the distinct ones).

The product of its digits is 6144, while the sum is 32.

The square root of 21641288 is about 4652.0197763982. The cubic root of 21641288 is about 278.6726632970.

The spelling of 21641288 in words is "twenty-one million, six hundred forty-one thousand, two hundred eighty-eight".