21849541 has 12 divisors (see below), whose sum is σ = 25684428. Its totient is φ = 18531072.

The previous prime is 21849523. The next prime is 21849551. The reversal of 21849541 is 14594812.

It is a happy number.

21849541 is nontrivially palindromic in base 4.

It can be written as a sum of positive squares in 2 ways, for example, as 5080516 + 16769025 = 2254^2 + 4095^2 .

It is not a de Polignac number, because 21849541 - 2⁷ = 21849413 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21849497 and 21849506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21849511) 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 11 ways as a sum of consecutive naturals, for example, 2455 + ... + 7051.

It is an arithmetic number, because the mean of its divisors is an integer number (2140369).

Almost surely, 2^21849541 is an apocalyptic number.

It is an amenable number.

21849541 is a deficient number, since it is larger than the sum of its proper divisors (3834887).

21849541 is an equidigital number, since it uses as much as digits as its factorization.

21849541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4708 (or 4701 counting only the distinct ones).

The product of its digits is 11520, while the sum is 34.

The square root of 21849541 is about 4674.3492595227. The cubic root of 21849541 is about 279.5636954902.

The spelling of 21849541 in words is "twenty-one million, eight hundred forty-nine thousand, five hundred forty-one".