21818841 has 12 divisors (see below), whose sum is σ = 31977456. Its totient is φ = 13223320.

The previous prime is 21818833. The next prime is 21818851. The reversal of 21818841 is 14881812.

It is not a de Polignac number, because 21818841 - 2³ = 21818833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21818801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29691 + ... + 30416.

It is an arithmetic number, because the mean of its divisors is an integer number (2664788).

Almost surely, 2^21818841 is an apocalyptic number.

It is an amenable number.

21818841 is a deficient number, since it is larger than the sum of its proper divisors (10158615).

21818841 is a wasteful number, since it uses less digits than its factorization.

21818841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60132 (or 60121 counting only the distinct ones).

The product of its digits is 4096, while the sum is 33.

The square root of 21818841 is about 4671.0642256342. The cubic root of 21818841 is about 279.4326991717.

The spelling of 21818841 in words is "twenty-one million, eight hundred eighteen thousand, eight hundred forty-one".