21540841 has 12 divisors (see below), whose sum is σ = 25485840. Its totient is φ = 18148200.

The previous prime is 21540833. The next prime is 21540847. The reversal of 21540841 is 14804512.

It is not a de Polignac number, because 21540841 - 2³ = 21540833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21540847) 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, 835 + ... + 6616.

It is an arithmetic number, because the mean of its divisors is an integer number (2123820).

Almost surely, 2^21540841 is an apocalyptic number.

It is an amenable number.

21540841 is a deficient number, since it is larger than the sum of its proper divisors (3944999).

21540841 is an equidigital number, since it uses as much as digits as its factorization.

21540841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7524 (or 7517 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 21540841 is about 4641.2111565840. The cubic root of 21540841 is about 278.2408459206.

The spelling of 21540841 in words is "twenty-one million, five hundred forty thousand, eight hundred forty-one".