645346078081 has 16 divisors (see below), whose sum is σ = 655641604800. Its totient is φ = 635120282368.

The previous prime is 645346078067. The next prime is 645346078087. The reversal of 645346078081 is 180870643546.

It is a cyclic number.

It is not a de Polignac number, because 645346078081 - 2⁵ = 645346078049 is a prime.

It is a super-2 number, since 2×645346078081² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645346078087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88315230 + ... + 88322536.

It is an arithmetic number, because the mean of its divisors is an integer number (40977600300).

Almost surely, 2^645346078081 is an apocalyptic number.

It is an amenable number.

645346078081 is a deficient number, since it is larger than the sum of its proper divisors (10295526719).

645346078081 is a wasteful number, since it uses less digits than its factorization.

645346078081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11888.

The product of its (nonzero) digits is 3870720, while the sum is 52.

The spelling of 645346078081 in words is "six hundred forty-five billion, three hundred forty-six million, seventy-eight thousand, eighty-one".