645115800 has 192 divisors, whose sum is σ = 2298067200. Its totient is φ = 146649600.

The previous prime is 645115781. The next prime is 645115811. The reversal of 645115800 is 8511546.

It is a Harshad number since it is a multiple of its sum of digits (30).

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 47 ways as a sum of consecutive naturals, for example, 1129515 + ... + 1130085.

It is an arithmetic number, because the mean of its divisors is an integer number (11969100).

Almost surely, 2^645115800 is an apocalyptic number.

645115800 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 645115800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1149033600).

645115800 is an abundant number, since it is smaller than the sum of its proper divisors (1652951400).

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

645115800 is a wasteful number, since it uses less digits than its factorization.

645115800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 866 (or 857 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 645115800 is about 25399.1299063570. The cubic root of 645115800 is about 864.0639634573.

The spelling of 645115800 in words is "six hundred forty-five million, one hundred fifteen thousand, eight hundred".