43123021 has 4 divisors (see below), whose sum is σ = 44174844. Its totient is φ = 42071200.

The previous prime is 43123007. The next prime is 43123037. The reversal of 43123021 is 12032134.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12032134 = 2 ⋅6016067.

It can be written as a sum of positive squares in 2 ways, for example, as 24890121 + 18232900 = 4989^2 + 4270^2 .

It is a cyclic number.

It is not a de Polignac number, because 43123021 - 2¹⁵ = 43090253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 43122986 and 43123004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43123001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525850 + ... + 525931.

It is an arithmetic number, because the mean of its divisors is an integer number (11043711).

Almost surely, 2^43123021 is an apocalyptic number.

43123021 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

43123021 is a deficient number, since it is larger than the sum of its proper divisors (1051823).

43123021 is a wasteful number, since it uses less digits than its factorization.

43123021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051822.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 43123021 is about 6566.8120880683. The cubic root of 43123021 is about 350.6735898908.

Adding to 43123021 its reverse (12032134), we get a palindrome (55155155).

The spelling of 43123021 in words is "forty-three million, one hundred twenty-three thousand, twenty-one".