43723421 has 4 divisors (see below), whose sum is σ = 49969632. Its totient is φ = 37477212.

The previous prime is 43723417. The next prime is 43723469. The reversal of 43723421 is 12432734.

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: 12432734 = 2 ⋅6216367.

It is a cyclic number.

It is not a de Polignac number, because 43723421 - 2² = 43723417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43723481) 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, 3123095 + ... + 3123108.

It is an arithmetic number, because the mean of its divisors is an integer number (12492408).

Almost surely, 2^43723421 is an apocalyptic number.

It is an amenable number.

43723421 is a deficient number, since it is larger than the sum of its proper divisors (6246211).

43723421 is an equidigital number, since it uses as much as digits as its factorization.

43723421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6246210.

The product of its digits is 4032, while the sum is 26.

The square root of 43723421 is about 6612.3687888683. The cubic root of 43723421 is about 352.2935658995.

It can be divided in two parts, 43723 and 421, that added together give a palindrome (44144).

The spelling of 43723421 in words is "forty-three million, seven hundred twenty-three thousand, four hundred twenty-one".