40818391 has 2 divisors, whose sum is σ = 40818392. Its totient is φ = 40818390.

The previous prime is 40818359. The next prime is 40818409. The reversal of 40818391 is 19381804.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 40818391 - 2⁵ = 40818359 is a prime.

It is a super-2 number, since 2×40818391² = 3332282087657762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40818311) 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, 20409195 + 20409196.

It is an arithmetic number, because the mean of its divisors is an integer number (20409196).

Almost surely, 2^40818391 is an apocalyptic number.

40818391 is a deficient number, since it is larger than the sum of its proper divisors (1).

40818391 is an equidigital number, since it uses as much as digits as its factorization.

40818391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 40818391 is about 6388.9272182425. The cubic root of 40818391 is about 344.3118425839.

It can be divided in two parts, 40818 and 391, that added together give a square (41209 = 203²).

The spelling of 40818391 in words is "forty million, eight hundred eighteen thousand, three hundred ninety-one".