645666375140 has 24 divisors (see below), whose sum is σ = 1355924965752. Its totient is φ = 258261678080.

The previous prime is 645666375131. The next prime is 645666375149. The reversal of 645666375140 is 41573666546.

It is an interprime number because it is at equal distance from previous prime (645666375131) and next prime (645666375149).

It can be written as a sum of positive squares in 4 ways, for example, as 33942166756 + 611724208384 = 184234^2 + 782128^2 .

It is not an unprimeable number, because it can be changed into a prime (645666375149) 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 7 ways as a sum of consecutive naturals, for example, 898052 + ... + 1448388.

It is an arithmetic number, because the mean of its divisors is an integer number (56496873573).

Almost surely, 2^645666375140 is an apocalyptic number.

It is an amenable number.

645666375140 is an abundant number, since it is smaller than the sum of its proper divisors (710258590612).

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

645666375140 is a wasteful number, since it uses less digits than its factorization.

645666375140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609007 (or 609005 counting only the distinct ones).

The product of its (nonzero) digits is 10886400, while the sum is 53.

The spelling of 645666375140 in words is "six hundred forty-five billion, six hundred sixty-six million, three hundred seventy-five thousand, one hundred forty".