645606556080 has 480 divisors, whose sum is σ = 2196296410176. Its totient is φ = 156732162048.

The previous prime is 645606556079. The next prime is 645606556093. The reversal of 645606556080 is 80655606546.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 505564402 + ... + 505565678.

Almost surely, 2^645606556080 is an apocalyptic number.

645606556080 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645606556080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1098148205088).

645606556080 is an abundant number, since it is smaller than the sum of its proper divisors (1550689854096).

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

645606556080 is a wasteful number, since it uses less digits than its factorization.

645606556080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1561 (or 1538 counting only the distinct ones).

The product of its (nonzero) digits is 5184000, while the sum is 51.

The spelling of 645606556080 in words is "six hundred forty-five billion, six hundred six million, five hundred fifty-six thousand, eighty".