40543991 has 2 divisors, whose sum is σ = 40543992. Its totient is φ = 40543990.

The previous prime is 40543973. The next prime is 40543999. The reversal of 40543991 is 19934504.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 40543991 - 2⁶ = 40543927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40543999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20271995 + 20271996.

It is an arithmetic number, because the mean of its divisors is an integer number (20271996).

Almost surely, 2^40543991 is an apocalyptic number.

40543991 is a deficient number, since it is larger than the sum of its proper divisors (1).

40543991 is an equidigital number, since it uses as much as digits as its factorization.

40543991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 40543991 is about 6367.4163520222. The cubic root of 40543991 is about 343.5385663528.

The spelling of 40543991 in words is "forty million, five hundred forty-three thousand, nine hundred ninety-one".