43125721 has 4 divisors (see below), whose sum is σ = 43645392. Its totient is φ = 42606052.

The previous prime is 43125703. The next prime is 43125749. The reversal of 43125721 is 12752134.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 43125721 - 2²¹ = 41028569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43125701) 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, 259711 + ... + 259876.

It is an arithmetic number, because the mean of its divisors is an integer number (10911348).

Almost surely, 2^43125721 is an apocalyptic number.

It is an amenable number.

43125721 is a deficient number, since it is larger than the sum of its proper divisors (519671).

43125721 is an equidigital number, since it uses as much as digits as its factorization.

43125721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519670.

The product of its digits is 1680, while the sum is 25.

The square root of 43125721 is about 6567.0176640542. The cubic root of 43125721 is about 350.6809084793.

Adding to 43125721 its reverse (12752134), we get a palindrome (55877855).

The spelling of 43125721 in words is "forty-three million, one hundred twenty-five thousand, seven hundred twenty-one".