18638646629 has 2 divisors, whose sum is σ = 18638646630. Its totient is φ = 18638646628.

The previous prime is 18638646599. The next prime is 18638646661. The reversal of 18638646629 is 92664683681.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15123342529 + 3515304100 = 122977^2 + 59290^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18638646629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18638646679) 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, 9319323314 + 9319323315.

It is an arithmetic number, because the mean of its divisors is an integer number (9319323315).

Almost surely, 2^18638646629 is an apocalyptic number.

It is an amenable number.

18638646629 is a deficient number, since it is larger than the sum of its proper divisors (1).

18638646629 is an equidigital number, since it uses as much as digits as its factorization.

18638646629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17915904, while the sum is 59.

The spelling of 18638646629 in words is "eighteen billion, six hundred thirty-eight million, six hundred forty-six thousand, six hundred twenty-nine".