66555215457 has 4 divisors (see below), whose sum is σ = 88740287280. Its totient is φ = 44370143636.

The previous prime is 66555215453. The next prime is 66555215479. The reversal of 66555215457 is 75451255566.

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 66555215457 - 2² = 66555215453 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66555215453) 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, 11092535907 + ... + 11092535912.

It is an arithmetic number, because the mean of its divisors is an integer number (22185071820).

Almost surely, 2^66555215457 is an apocalyptic number.

It is an amenable number.

66555215457 is a deficient number, since it is larger than the sum of its proper divisors (22185071823).

66555215457 is a wasteful number, since it uses less digits than its factorization.

66555215457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22185071822.

The product of its digits is 6300000, while the sum is 51.

The spelling of 66555215457 in words is "sixty-six billion, five hundred fifty-five million, two hundred fifteen thousand, four hundred fifty-seven".