645405600 has 288 divisors, whose sum is σ = 2462092416. Its totient is φ = 143769600.

The previous prime is 645405571. The next prime is 645405601. The reversal of 645405600 is 6504546.

It is a super-2 number, since 2×645405600² = 833096777022720000, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (645405601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 688332 + ... + 689268.

It is an arithmetic number, because the mean of its divisors is an integer number (8548932).

Almost surely, 2^645405600 is an apocalyptic number.

645405600 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 645405600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1231046208).

645405600 is an abundant number, since it is smaller than the sum of its proper divisors (1816686816).

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

645405600 is a wasteful number, since it uses less digits than its factorization.

645405600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008 (or 995 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

The square root of 645405600 is about 25404.8341856427. The cubic root of 645405600 is about 864.1933295081.

645405600 divided by its sum of digits (30) gives a triangular number (21513520 = T₆₅₅₉).

The spelling of 645405600 in words is "six hundred forty-five million, four hundred five thousand, six hundred".