21484181 has 4 divisors (see below), whose sum is σ = 21595692. Its totient is φ = 21372672.

The previous prime is 21484163. The next prime is 21484187. The reversal of 21484181 is 18148412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11662225 + 9821956 = 3415^2 + 3134^2 .

It is a cyclic number.

It is not a de Polignac number, because 21484181 - 2¹⁰ = 21483157 is a prime.

It is a super-2 number, since 2×21484181² = 923140066481522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21484187) 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, 55466 + ... + 55851.

It is an arithmetic number, because the mean of its divisors is an integer number (5398923).

Almost surely, 2^21484181 is an apocalyptic number.

It is an amenable number.

21484181 is a deficient number, since it is larger than the sum of its proper divisors (111511).

21484181 is a wasteful number, since it uses less digits than its factorization.

21484181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111510.

The product of its digits is 2048, while the sum is 29.

The square root of 21484181 is about 4635.1031272238. The cubic root of 21484181 is about 277.9966745630.

The spelling of 21484181 in words is "twenty-one million, four hundred eighty-four thousand, one hundred eighty-one".