21641330 has 16 divisors (see below), whose sum is σ = 39334464. Its totient is φ = 8572080.

The previous prime is 21641311. The next prime is 21641353. The reversal of 21641330 is 3314612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9476 + ... + 11535.

It is an arithmetic number, because the mean of its divisors is an integer number (2458404).

Almost surely, 2^21641330 is an apocalyptic number.

21641330 is a deficient number, since it is larger than the sum of its proper divisors (17693134).

21641330 is a wasteful number, since it uses less digits than its factorization.

21641330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21121.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 21641330 is about 4652.0242905643. The cubic root of 21641330 is about 278.6728435734.

Adding to 21641330 its reverse (3314612), we get a palindrome (24955942).

The spelling of 21641330 in words is "twenty-one million, six hundred forty-one thousand, three hundred thirty".