645004080 has 320 divisors, whose sum is σ = 2628403200. Its totient is φ = 142248960.

The previous prime is 645004069. The next prime is 645004097. The reversal of 645004080 is 80400546.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 437745 + ... + 439215.

It is an arithmetic number, because the mean of its divisors is an integer number (8213760).

Almost surely, 2^645004080 is an apocalyptic number.

645004080 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 645004080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1314201600).

645004080 is an abundant number, since it is smaller than the sum of its proper divisors (1983399120).

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

645004080 is a wasteful number, since it uses less digits than its factorization.

645004080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1529 (or 1517 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 645004080 is about 25396.9305231951. The cubic root of 645004080 is about 864.0140815606.

The spelling of 645004080 in words is "six hundred forty-five million, four thousand, eighty".