21804741 has 32 divisors (see below), whose sum is σ = 37790720. Its totient is φ = 12165552.

The previous prime is 21804737. The next prime is 21804779. The reversal of 21804741 is 14740812.

It is not a de Polignac number, because 21804741 - 2² = 21804737 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21804701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6786 + ... + 9468.

It is an arithmetic number, because the mean of its divisors is an integer number (1180960).

Almost surely, 2^21804741 is an apocalyptic number.

21804741 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21804741 is a deficient number, since it is larger than the sum of its proper divisors (15985979).

21804741 is a wasteful number, since it uses less digits than its factorization.

21804741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2742 (or 2736 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21804741 is about 4669.5546896894. The cubic root of 21804741 is about 279.3724935589.

The spelling of 21804741 in words is "twenty-one million, eight hundred four thousand, seven hundred forty-one".