645131102120 has 64 divisors (see below), whose sum is σ = 1537660771920. Its totient is φ = 242757402624.

The previous prime is 645131102113. The next prime is 645131102129. The reversal of 645131102120 is 21201131546.

It can be written as a sum of positive squares in 8 ways, for example, as 94712524516 + 550418577604 = 307754^2 + 741902^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 645131102120.

It is not an unprimeable number, because it can be changed into a prime (645131102129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1212344 + ... + 1661336.

Almost surely, 2^645131102120 is an apocalyptic number.

It is an amenable number.

645131102120 is an abundant number, since it is smaller than the sum of its proper divisors (892529669800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645131102120 is a wasteful number, since it uses less digits than its factorization.

645131102120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451134 (or 451130 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

Adding to 645131102120 its reverse (21201131546), we get a palindrome (666332233666).

The spelling of 645131102120 in words is "six hundred forty-five billion, one hundred thirty-one million, one hundred two thousand, one hundred twenty".