12643557 has 4 divisors (see below), whose sum is σ = 16858080. Its totient is φ = 8429036.

The previous prime is 12643549. The next prime is 12643571. The reversal of 12643557 is 75534621.

12643557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 12643557 - 2³ = 12643549 is a prime.

It is a super-2 number, since 2×12643557² = 319719067224498, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12623557) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2107257 + ... + 2107262.

It is an arithmetic number, because the mean of its divisors is an integer number (4214520).

Almost surely, 2^12643557 is an apocalyptic number.

It is an amenable number.

12643557 is a deficient number, since it is larger than the sum of its proper divisors (4214523).

12643557 is an equidigital number, since it uses as much as digits as its factorization.

12643557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214522.

The product of its digits is 25200, while the sum is 33.

The square root of 12643557 is about 3555.7779739461. Note that the first 3 decimals coincide. The cubic root of 12643557 is about 232.9645055131.

The spelling of 12643557 in words is "twelve million, six hundred forty-three thousand, five hundred fifty-seven".