43031381 has 2 divisors, whose sum is σ = 43031382. Its totient is φ = 43031380.

The previous prime is 43031377. The next prime is 43031393. The reversal of 43031381 is 18313034.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42902500 + 128881 = 6550^2 + 359^2 .

It is a cyclic number.

It is not a de Polignac number, because 43031381 - 2² = 43031377 is a prime.

It is a super-2 number, since 2×43031381² = 3703399501534322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43031081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21515690 + 21515691.

It is an arithmetic number, because the mean of its divisors is an integer number (21515691).

Almost surely, 2^43031381 is an apocalyptic number.

It is an amenable number.

43031381 is a deficient number, since it is larger than the sum of its proper divisors (1).

43031381 is an equidigital number, since it uses as much as digits as its factorization.

43031381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 43031381 is about 6559.8308667221. The cubic root of 43031381 is about 350.4250102254.

The spelling of 43031381 in words is "forty-three million, thirty-one thousand, three hundred eighty-one".