645155280 has 480 divisors, whose sum is σ = 2807820288. Its totient is φ = 133747200.

The previous prime is 645155243. The next prime is 645155293. The reversal of 645155280 is 82551546.

645155280 is a `hidden beast` number, since 64 + 515 + 5 + 2 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 1496665 + ... + 1497095.

Almost surely, 2^645155280 is an apocalyptic number.

645155280 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 645155280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1403910144).

645155280 is an abundant number, since it is smaller than the sum of its proper divisors (2162665008).

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

645155280 is a wasteful number, since it uses less digits than its factorization.

645155280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 459 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

The square root of 645155280 is about 25399.9070864442. The cubic root of 645155280 is about 864.0815895173.

The spelling of 645155280 in words is "six hundred forty-five million, one hundred fifty-five thousand, two hundred eighty".