43672721 has 4 divisors (see below), whose sum is σ = 44096832. Its totient is φ = 43248612.

The previous prime is 43672693. The next prime is 43672763. The reversal of 43672721 is 12727634.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12727634 = 2 ⋅6363817.

It is a cyclic number.

It is not a de Polignac number, because 43672721 - 2¹⁰ = 43671697 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 (43672021) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 211901 + ... + 212106.

It is an arithmetic number, because the mean of its divisors is an integer number (11024208).

Almost surely, 2^43672721 is an apocalyptic number.

It is an amenable number.

43672721 is a deficient number, since it is larger than the sum of its proper divisors (424111).

43672721 is a wasteful number, since it uses less digits than its factorization.

43672721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424110.

The product of its digits is 14112, while the sum is 32.

The square root of 43672721 is about 6608.5339523982. The cubic root of 43672721 is about 352.1573445366.

The spelling of 43672721 in words is "forty-three million, six hundred seventy-two thousand, seven hundred twenty-one".