40491389 has 4 divisors (see below), whose sum is σ = 40908924. Its totient is φ = 40073856.

The previous prime is 40491379. The next prime is 40491391. The reversal of 40491389 is 98319404.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33292900 + 7198489 = 5770^2 + 2683^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40491389 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40491349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208622 + ... + 208815.

It is an arithmetic number, because the mean of its divisors is an integer number (10227231).

Almost surely, 2^40491389 is an apocalyptic number.

It is an amenable number.

40491389 is a deficient number, since it is larger than the sum of its proper divisors (417535).

40491389 is an equidigital number, since it uses as much as digits as its factorization.

40491389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417534.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 40491389 is about 6363.2844506591. The cubic root of 40491389 is about 343.3899324375.

The spelling of 40491389 in words is "forty million, four hundred ninety-one thousand, three hundred eighty-nine".