43404021 has 6 divisors (see below), whose sum is σ = 62694710. Its totient is φ = 28936008.

The previous prime is 43404019. The next prime is 43404029. The reversal of 43404021 is 12040434.

It can be written as a sum of positive squares in only one way, i.e., 43164900 + 239121 = 6570^2 + 489^2 .

It is not a de Polignac number, because 43404021 - 2¹ = 43404019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 43403985 and 43404003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43404029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2411326 + ... + 2411343.

Almost surely, 2^43404021 is an apocalyptic number.

It is an amenable number.

43404021 is a deficient number, since it is larger than the sum of its proper divisors (19290689).

43404021 is a wasteful number, since it uses less digits than its factorization.

43404021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4822675 (or 4822672 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 43404021 is about 6588.1728119411. The cubic root of 43404021 is about 351.4336326146.

Adding to 43404021 its reverse (12040434), we get a palindrome (55444455).

It can be divided in two parts, 4 and 3404021, that added together give a square (3404025 = 1845²).

The spelling of 43404021 in words is "forty-three million, four hundred four thousand, twenty-one".