27643343657 has 4 divisors (see below), whose sum is σ = 27644398080. Its totient is φ = 27642289236.

The previous prime is 27643343633. The next prime is 27643343671. The reversal of 27643343657 is 75634334672.

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 a de Polignac number, because none of the positive numbers 2^k-27643343657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27643343627) 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, 486857 + ... + 540662.

It is an arithmetic number, because the mean of its divisors is an integer number (6911099520).

Almost surely, 2^27643343657 is an apocalyptic number.

It is an amenable number.

27643343657 is a deficient number, since it is larger than the sum of its proper divisors (1054423).

27643343657 is a wasteful number, since it uses less digits than its factorization.

27643343657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1054422.

The product of its digits is 7620480, while the sum is 50.

The spelling of 27643343657 in words is "twenty-seven billion, six hundred forty-three million, three hundred forty-three thousand, six hundred fifty-seven".