43309381 has 4 divisors (see below), whose sum is σ = 43375564. Its totient is φ = 43243200.

The previous prime is 43309349. The next prime is 43309423. The reversal of 43309381 is 18390334.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18390334 = 2 ⋅9195167.

It can be written as a sum of positive squares in 2 ways, for example, as 29877156 + 13432225 = 5466^2 + 3665^2 .

It is a cyclic number.

It is not a de Polignac number, because 43309381 - 2⁵ = 43309349 is a prime.

It is a super-2 number, since 2×43309381² = 3751404965206322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43309181) 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, 32100 + ... + 33421.

It is an arithmetic number, because the mean of its divisors is an integer number (10843891).

Almost surely, 2^43309381 is an apocalyptic number.

It is an amenable number.

43309381 is a deficient number, since it is larger than the sum of its proper divisors (66183).

43309381 is an equidigital number, since it uses as much as digits as its factorization.

43309381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66182.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 43309381 is about 6580.9863242526. The cubic root of 43309381 is about 351.1780197231.

The spelling of 43309381 in words is "forty-three million, three hundred nine thousand, three hundred eighty-one".