12639986 has 4 divisors (see below), whose sum is σ = 18959982. Its totient is φ = 6319992.

The previous prime is 12639961. The next prime is 12639989. The reversal of 12639986 is 68993621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 7187761 + 5452225 = 2681^2 + 2335^2 .

It is not an unprimeable number, because it can be changed into a prime (12639989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3159995 + ... + 3159998.

Almost surely, 2^12639986 is an apocalyptic number.

12639986 is a deficient number, since it is larger than the sum of its proper divisors (6319996).

12639986 is an equidigital number, since it uses as much as digits as its factorization.

12639986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6319995.

The product of its digits is 139968, while the sum is 44.

The square root of 12639986 is about 3555.2757980219. The cubic root of 12639986 is about 232.9425709003.

The spelling of 12639986 in words is "twelve million, six hundred thirty-nine thousand, nine hundred eighty-six".