21550541 has 4 divisors (see below), whose sum is σ = 22684800. Its totient is φ = 20416284.

The previous prime is 21550537. The next prime is 21550547. The reversal of 21550541 is 14505512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21550541 - 2² = 21550537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550547) 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 3 ways as a sum of consecutive naturals, for example, 567101 + ... + 567138.

It is an arithmetic number, because the mean of its divisors is an integer number (5671200).

Almost surely, 2^21550541 is an apocalyptic number.

It is an amenable number.

21550541 is a deficient number, since it is larger than the sum of its proper divisors (1134259).

21550541 is a wasteful number, since it uses less digits than its factorization.

21550541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1134258.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 21550541 is about 4642.2560248224. The cubic root of 21550541 is about 278.2826042901.

The spelling of 21550541 in words is "twenty-one million, five hundred fifty thousand, five hundred forty-one".