645466664545 has 4 divisors (see below), whose sum is σ = 774559997460. Its totient is φ = 516373331632.

The previous prime is 645466664497. The next prime is 645466664551. The reversal of 645466664545 is 545466664546.

It is a happy number.

645466664545 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 406318279761 + 239148384784 = 637431^2 + 489028^2 .

It is a cyclic number.

It is not a de Polignac number, because 645466664545 - 2⁷ = 645466664417 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64546666450 + ... + 64546666459.

It is an arithmetic number, because the mean of its divisors is an integer number (193639999365).

Almost surely, 2^645466664545 is an apocalyptic number.

It is an amenable number.

645466664545 is a deficient number, since it is larger than the sum of its proper divisors (129093332915).

645466664545 is a wasteful number, since it uses less digits than its factorization.

645466664545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129093332914.

The product of its digits is 248832000, while the sum is 61.

Subtracting from 645466664545 its reverse (545466664546), we obtain a palindrome (99999999999).

The spelling of 645466664545 in words is "six hundred forty-five billion, four hundred sixty-six million, six hundred sixty-four thousand, five hundred forty-five".