21844641 has 64 divisors (see below), whose sum is σ = 38707200. Its totient is φ = 10866240.

The previous prime is 21844637. The next prime is 21844651. The reversal of 21844641 is 14644812.

It is not a de Polignac number, because 21844641 - 2² = 21844637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21844599 and 21844608.

It is not an unprimeable number, because it can be changed into a prime (21844601) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 307636 + ... + 307706.

It is an arithmetic number, because the mean of its divisors is an integer number (604800).

Almost surely, 2^21844641 is an apocalyptic number.

21844641 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21844641 is a deficient number, since it is larger than the sum of its proper divisors (16862559).

21844641 is a wasteful number, since it uses less digits than its factorization.

21844641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 117 counting only the distinct ones).

The product of its digits is 6144, while the sum is 30.

The square root of 21844641 is about 4673.8250930047. The cubic root of 21844641 is about 279.5427955161.

The spelling of 21844641 in words is "twenty-one million, eight hundred forty-four thousand, six hundred forty-one".