645123484321547 has 64 divisors (see below), whose sum is σ = 828354642508800. Its totient is φ = 487898931886080.

The previous prime is 645123484321543. The next prime is 645123484321577. The reversal of 645123484321547 is 745123484321546.

It is a happy number.

It is not a de Polignac number, because 645123484321547 - 2² = 645123484321543 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is not an unprimeable number, because it can be changed into a prime (645123484321543) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 272550983 + ... + 274907775.

It is an arithmetic number, because the mean of its divisors is an integer number (12943041289200).

Almost surely, 2^{645123484321547} is an apocalyptic number.

645123484321547 is a deficient number, since it is larger than the sum of its proper divisors (183231158187253).

645123484321547 is a wasteful number, since it uses less digits than its factorization.

645123484321547 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2357636.

The product of its digits is 77414400, while the sum is 59.

Subtracting 645123484321547 from its reverse (745123484321546), we obtain a palindrome (99999999999999).

The spelling of 645123484321547 in words is "six hundred forty-five trillion, one hundred twenty-three billion, four hundred eighty-four million, three hundred twenty-one thousand, five hundred forty-seven".