21641804 has 24 divisors (see below), whose sum is σ = 40121088. Its totient is φ = 10193040.

The previous prime is 21641797. The next prime is 21641831. The reversal of 21641804 is 40814612.

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, 4409 + ... + 7919.

It is an arithmetic number, because the mean of its divisors is an integer number (1671712).

Almost surely, 2^21641804 is an apocalyptic number.

It is an amenable number.

21641804 is a deficient number, since it is larger than the sum of its proper divisors (18479284).

21641804 is a wasteful number, since it uses less digits than its factorization.

21641804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3605 (or 3603 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 21641804 is about 4652.0752358491. The cubic root of 21641804 is about 278.6748781059.

The spelling of 21641804 in words is "twenty-one million, six hundred forty-one thousand, eight hundred four".