12639817 has 2 divisors, whose sum is σ = 12639818. Its totient is φ = 12639816.

The previous prime is 12639793. The next prime is 12639827. The reversal of 12639817 is 71893621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8433216 + 4206601 = 2904^2 + 2051^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12639817 is a prime.

It is not a weakly prime, because it can be changed into another prime (12639827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6319908 + 6319909.

It is an arithmetic number, because the mean of its divisors is an integer number (6319909).

Almost surely, 2^12639817 is an apocalyptic number.

It is an amenable number.

12639817 is a deficient number, since it is larger than the sum of its proper divisors (1).

12639817 is an equidigital number, since it uses as much as digits as its factorization.

12639817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 12639817 is about 3555.2520304473. The cubic root of 12639817 is about 232.9415327275.

It can be divided in two parts, 12639 and 817, that added together give a square (13456 = 116²).

The spelling of 12639817 in words is "twelve million, six hundred thirty-nine thousand, eight hundred seventeen".