12787657 has 4 divisors (see below), whose sum is σ = 12795136. Its totient is φ = 12780180.

The previous prime is 12787639. The next prime is 12787667. The reversal of 12787657 is 75678721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 75678721 = 97 ⋅780193.

It is a cyclic number.

It is not a de Polignac number, because 12787657 - 2¹⁹ = 12263369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12787667) 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 in 3 ways as a sum of consecutive naturals, for example, 232 + ... + 5062.

It is an arithmetic number, because the mean of its divisors is an integer number (3198784).

Almost surely, 2^12787657 is an apocalyptic number.

It is an amenable number.

12787657 is a deficient number, since it is larger than the sum of its proper divisors (7479).

12787657 is an equidigital number, since it uses as much as digits as its factorization.

12787657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7478.

The product of its digits is 164640, while the sum is 43.

The square root of 12787657 is about 3575.9833612588. The cubic root of 12787657 is about 233.8462049778.

The spelling of 12787657 in words is "twelve million, seven hundred eighty-seven thousand, six hundred fifty-seven".