43070921 has 4 divisors (see below), whose sum is σ = 43127700. Its totient is φ = 43014144.

The previous prime is 43070917. The next prime is 43070933. The reversal of 43070921 is 12907034.

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 30680521 + 12390400 = 5539^2 + 3520^2 .

It is a cyclic number.

It is not a de Polignac number, because 43070921 - 2² = 43070917 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (43070971) 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, 27236 + ... + 28773.

It is an arithmetic number, because the mean of its divisors is an integer number (10781925).

Almost surely, 2^43070921 is an apocalyptic number.

It is an amenable number.

43070921 is a deficient number, since it is larger than the sum of its proper divisors (56779).

43070921 is an equidigital number, since it uses as much as digits as its factorization.

43070921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56778.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 43070921 is about 6562.8439719378. The cubic root of 43070921 is about 350.5323083792.

Adding to 43070921 its reverse (12907034), we get a palindrome (55977955).

The spelling of 43070921 in words is "forty-three million, seventy thousand, nine hundred twenty-one".