40640399 has 2 divisors, whose sum is σ = 40640400. Its totient is φ = 40640398.

The previous prime is 40640363. The next prime is 40640417. The reversal of 40640399 is 99304604.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 40640399 - 2¹² = 40636303 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40640599) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20320199 + 20320200.

It is an arithmetic number, because the mean of its divisors is an integer number (20320200).

Almost surely, 2^40640399 is an apocalyptic number.

40640399 is a deficient number, since it is larger than the sum of its proper divisors (1).

40640399 is an equidigital number, since it uses as much as digits as its factorization.

40640399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 40640399 is about 6374.9822744852. The cubic root of 40640399 is about 343.8106465339.

The spelling of 40640399 in words is "forty million, six hundred forty thousand, three hundred ninety-nine".