40018391 has 16 divisors (see below), whose sum is σ = 48593664. Its totient is φ = 32171904.

The previous prime is 40018373. The next prime is 40018393. The reversal of 40018391 is 19381004.

40018391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 40018391 - 2⁶ = 40018327 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 40018391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40018393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61916 + ... + 62558.

It is an arithmetic number, because the mean of its divisors is an integer number (3037104).

Almost surely, 2^40018391 is an apocalyptic number.

40018391 is a deficient number, since it is larger than the sum of its proper divisors (8575273).

40018391 is a wasteful number, since it uses less digits than its factorization.

40018391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1190.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 40018391 is about 6326.0090894655. The cubic root of 40018391 is about 342.0475949173.

Adding to 40018391 its reverse (19381004), we get a palindrome (59399395).

The spelling of 40018391 in words is "forty million, eighteen thousand, three hundred ninety-one".