66256421635 has 4 divisors (see below), whose sum is σ = 79507705968. Its totient is φ = 53005137304.

The previous prime is 66256421617. The next prime is 66256421657. The reversal of 66256421635 is 53612465266.

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

It is a cyclic number.

It is not a de Polignac number, because 66256421635 - 2²¹ = 66254324483 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6625642159 + ... + 6625642168.

It is an arithmetic number, because the mean of its divisors is an integer number (19876926492).

Almost surely, 2^66256421635 is an apocalyptic number.

66256421635 is a deficient number, since it is larger than the sum of its proper divisors (13251284333).

66256421635 is a wasteful number, since it uses less digits than its factorization.

66256421635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13251284332.

The product of its digits is 1555200, while the sum is 46.

The spelling of 66256421635 in words is "sixty-six billion, two hundred fifty-six million, four hundred twenty-one thousand, six hundred thirty-five".