66647654401 has 4 divisors (see below), whose sum is σ = 66660933204. Its totient is φ = 66634375600.

The previous prime is 66647654387. The next prime is 66647654413. The reversal of 66647654401 is 10445674666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 64231833600 + 2415820801 = 253440^2 + 49151^2 .

It is a cyclic number.

It is not a de Polignac number, because 66647654401 - 2²⁵ = 66614099969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66647654441) 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, 6631870 + ... + 6641911.

It is an arithmetic number, because the mean of its divisors is an integer number (16665233301).

Almost surely, 2^66647654401 is an apocalyptic number.

It is an amenable number.

66647654401 is a deficient number, since it is larger than the sum of its proper divisors (13278803).

66647654401 is a wasteful number, since it uses less digits than its factorization.

66647654401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13278802.

The product of its (nonzero) digits is 2903040, while the sum is 49.

The spelling of 66647654401 in words is "sixty-six billion, six hundred forty-seven million, six hundred fifty-four thousand, four hundred one".