646225522645 has 4 divisors (see below), whose sum is σ = 775470627180. Its totient is φ = 516980418112.

The previous prime is 646225522643. The next prime is 646225522669. The reversal of 646225522645 is 546225522646.

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 69060160849 + 577165361796 = 262793^2 + 759714^2 .

It is a cyclic number.

It is not a de Polignac number, because 646225522645 - 2¹ = 646225522643 is a prime.

It is a super-2 number, since 2×646225522645² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646225522643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64622552260 + ... + 64622552269.

It is an arithmetic number, because the mean of its divisors is an integer number (193867656795).

Almost surely, 2^646225522645 is an apocalyptic number.

It is an amenable number.

646225522645 is a deficient number, since it is larger than the sum of its proper divisors (129245104535).

646225522645 is a wasteful number, since it uses less digits than its factorization.

646225522645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129245104534.

The product of its digits is 6912000, while the sum is 49.

Subtracting from 646225522645 its reverse (546225522646), we obtain a palindrome (99999999999).

The spelling of 646225522645 in words is "six hundred forty-six billion, two hundred twenty-five million, five hundred twenty-two thousand, six hundred forty-five".