21471844 has 6 divisors (see below), whose sum is σ = 37575734. Its totient is φ = 10735920.

The previous prime is 21471839. The next prime is 21471883. The reversal of 21471844 is 44817412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11985444 + 9486400 = 3462^2 + 3080^2 .

It is a super-3 number, since 3×21471844³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2683977 + ... + 2683984.

Almost surely, 2^21471844 is an apocalyptic number.

It is an amenable number.

21471844 is a deficient number, since it is larger than the sum of its proper divisors (16103890).

21471844 is a wasteful number, since it uses less digits than its factorization.

21471844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5367965 (or 5367963 counting only the distinct ones).

The product of its digits is 7168, while the sum is 31.

The square root of 21471844 is about 4633.7721135162. The cubic root of 21471844 is about 277.9434524324.

The spelling of 21471844 in words is "twenty-one million, four hundred seventy-one thousand, eight hundred forty-four".