645623540660 has 48 divisors (see below), whose sum is σ = 1549567536384. Its totient is φ = 221346494208.

The previous prime is 645623540651. The next prime is 645623540663. The reversal of 645623540660 is 66045326546.

It is a happy number.

It is a super-3 number, since 3×645623540660³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645623540663) 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 15 ways as a sum of consecutive naturals, for example, 3364217 + ... + 3550943.

It is an arithmetic number, because the mean of its divisors is an integer number (32282657008).

Almost surely, 2^645623540660 is an apocalyptic number.

It is an amenable number.

645623540660 is an abundant number, since it is smaller than the sum of its proper divisors (903943995724).

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

645623540660 is a wasteful number, since it uses less digits than its factorization.

645623540660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211440 (or 211438 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 47.

The spelling of 645623540660 in words is "six hundred forty-five billion, six hundred twenty-three million, five hundred forty thousand, six hundred sixty".