43131391 has 2 divisors, whose sum is σ = 43131392. Its totient is φ = 43131390.

The previous prime is 43131367. The next prime is 43131433. The reversal of 43131391 is 19313134.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43131391 - 2¹⁷ = 43000319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43101391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21565695 + 21565696.

It is an arithmetic number, because the mean of its divisors is an integer number (21565696).

Almost surely, 2^43131391 is an apocalyptic number.

43131391 is a deficient number, since it is larger than the sum of its proper divisors (1).

43131391 is an equidigital number, since it uses as much as digits as its factorization.

43131391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 25.

The square root of 43131391 is about 6567.4493526787. The cubic root of 43131391 is about 350.6962765208.

The spelling of 43131391 in words is "forty-three million, one hundred thirty-one thousand, three hundred ninety-one".