21641504 has 12 divisors (see below), whose sum is σ = 42606774. Its totient is φ = 10820736.

The previous prime is 21641483. The next prime is 21641509. The reversal of 21641504 is 40514612.

It can be written as a sum of positive squares in only one way, i.e., 21641104 + 400 = 4652^2 + 20^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21641504.

It is not an unprimeable number, because it can be changed into a prime (21641509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 338117 + ... + 338180.

Almost surely, 2^21641504 is an apocalyptic number.

It is an amenable number.

21641504 is a deficient number, since it is larger than the sum of its proper divisors (20965270).

21641504 is an equidigital number, since it uses as much as digits as its factorization.

21641504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676307 (or 676299 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21641504 is about 4652.0429920627. The cubic root of 21641504 is about 278.6735904305.

The spelling of 21641504 in words is "twenty-one million, six hundred forty-one thousand, five hundred four".