40663991 has 2 divisors, whose sum is σ = 40663992. Its totient is φ = 40663990.

The previous prime is 40663981. The next prime is 40664027. The reversal of 40663991 is 19936604.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40663991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40663981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20331995 + 20331996.

It is an arithmetic number, because the mean of its divisors is an integer number (20331996).

Almost surely, 2^40663991 is an apocalyptic number.

40663991 is a deficient number, since it is larger than the sum of its proper divisors (1).

40663991 is an equidigital number, since it uses as much as digits as its factorization.

40663991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 38.

The square root of 40663991 is about 6376.8323641131. The cubic root of 40663991 is about 343.8771617252.

The spelling of 40663991 in words is "forty million, six hundred sixty-three thousand, nine hundred ninety-one".