12640399 has 2 divisors, whose sum is σ = 12640400. Its totient is φ = 12640398.

The previous prime is 12640393. The next prime is 12640427. The reversal of 12640399 is 99304621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12640399 - 2¹⁵ = 12607631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12640393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6320199 + 6320200.

It is an arithmetic number, because the mean of its divisors is an integer number (6320200).

Almost surely, 2^12640399 is an apocalyptic number.

12640399 is a deficient number, since it is larger than the sum of its proper divisors (1).

12640399 is an equidigital number, since it uses as much as digits as its factorization.

12640399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 12640399 is about 3555.3338802425. Note that the first 3 decimals coincide. The cubic root of 12640399 is about 232.9451079346.

The spelling of 12640399 in words is "twelve million, six hundred forty thousand, three hundred ninety-nine".