645503385600 has 750 divisors, whose sum is σ = 2517253413620. Its totient is φ = 163074539520.

The previous prime is 645503385587. The next prime is 645503385623. The reversal of 645503385600 is 6583305546.

645503385600 is a `hidden beast` number, since 6 + 4 + 5 + 5 + 0 + 3 + 38 + 5 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 33973862391 + ... + 33973862409.

Almost surely, 2^645503385600 is an apocalyptic number.

645503385600 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 645503385600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1258626706810).

645503385600 is an abundant number, since it is smaller than the sum of its proper divisors (1871750028020).

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

645503385600 is an frugal number, since it uses more digits than its factorization.

645503385600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 645503385600 in words is "six hundred forty-five billion, five hundred three million, three hundred eighty-five thousand, six hundred".