1640636399 has 2 divisors, whose sum is σ = 1640636400. Its totient is φ = 1640636398.

The previous prime is 1640636363. The next prime is 1640636407. The reversal of 1640636399 is 9936360461.

It is a strong prime.

It is an emirp because it is prime and its reverse (9936360461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1640636399 - 2⁸ = 1640636143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640636099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820318199 + 820318200.

It is an arithmetic number, because the mean of its divisors is an integer number (820318200).

Almost surely, 2^1640636399 is an apocalyptic number.

1640636399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640636399 is an equidigital number, since it uses as much as digits as its factorization.

1640636399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 629856, while the sum is 47.

The square root of 1640636399 is about 40504.7700771156. The cubic root of 1640636399 is about 1179.4262266026.

The spelling of 1640636399 in words is "one billion, six hundred forty million, six hundred thirty-six thousand, three hundred ninety-nine".