21854541 has 16 divisors (see below), whose sum is σ = 30924800. Its totient is φ = 13689648.

The previous prime is 21854533. The next prime is 21854543. The reversal of 21854541 is 14545812.

It is not a de Polignac number, because 21854541 - 2³ = 21854533 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21854499 and 21854508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5730 + ... + 8748.

It is an arithmetic number, because the mean of its divisors is an integer number (1932800).

Almost surely, 2^21854541 is an apocalyptic number.

It is an amenable number.

21854541 is a deficient number, since it is larger than the sum of its proper divisors (9070259).

21854541 is a wasteful number, since it uses less digits than its factorization.

21854541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3168.

The product of its digits is 6400, while the sum is 30.

The square root of 21854541 is about 4674.8840627335. The cubic root of 21854541 is about 279.5850187736.

The spelling of 21854541 in words is "twenty-one million, eight hundred fifty-four thousand, five hundred forty-one".