645885240 has 512 divisors, whose sum is σ = 2748211200. Its totient is φ = 116951040.

The previous prime is 645885223. The next prime is 645885257. The reversal of 645885240 is 42588546.

It is an interprime number because it is at equal distance from previous prime (645885223) and next prime (645885257).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 645885192 and 645885201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2282139 + ... + 2282421.

It is an arithmetic number, because the mean of its divisors is an integer number (5367600).

Almost surely, 2^645885240 is an apocalyptic number.

645885240 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 645885240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1374105600).

645885240 is an abundant number, since it is smaller than the sum of its proper divisors (2102325960).

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

645885240 is a wasteful number, since it uses less digits than its factorization.

645885240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347 (or 343 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 42.

The square root of 645885240 is about 25414.2723681006. The cubic root of 645885240 is about 864.4073546371.

The spelling of 645885240 in words is "six hundred forty-five million, eight hundred eighty-five thousand, two hundred forty".