66540555647 has 16 divisors (see below), whose sum is σ = 69175959552. Its totient is φ = 63936586560.

The previous prime is 66540555643. The next prime is 66540555673. The reversal of 66540555647 is 74655504566.

It is a cyclic number.

It is not a de Polignac number, because 66540555647 - 2² = 66540555643 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66540555643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4926938 + ... + 4940424.

It is an arithmetic number, because the mean of its divisors is an integer number (4323497472).

Almost surely, 2^66540555647 is an apocalyptic number.

66540555647 is a deficient number, since it is larger than the sum of its proper divisors (2635403905).

66540555647 is a wasteful number, since it uses less digits than its factorization.

66540555647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14638.

The product of its (nonzero) digits is 15120000, while the sum is 53.

The spelling of 66540555647 in words is "sixty-six billion, five hundred forty million, five hundred fifty-five thousand, six hundred forty-seven".