645642180352 has 72 divisors (see below), whose sum is σ = 1388526327216. Its totient is φ = 297853771776.

The previous prime is 645642180341. The next prime is 645642180371. The reversal of 645642180352 is 253081246546.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7501788 + ... + 7587364.

It is an arithmetic number, because the mean of its divisors is an integer number (19285087878).

Almost surely, 2^645642180352 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645642180352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (694263163608).

645642180352 is an abundant number, since it is smaller than the sum of its proper divisors (742884146864).

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

645642180352 is a wasteful number, since it uses less digits than its factorization.

645642180352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87873 (or 87859 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 46.

The spelling of 645642180352 in words is "six hundred forty-five billion, six hundred forty-two million, one hundred eighty thousand, three hundred fifty-two".