645406560 has 72 divisors (see below), whose sum is σ = 2202454800. Its totient is φ = 172108032.

The previous prime is 645406469. The next prime is 645406579. The reversal of 645406560 is 65604546.

It is a happy number.

645406560 is a `hidden beast` number, since 64 + 540 + 6 + 56 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 222660 + ... + 225539.

It is an arithmetic number, because the mean of its divisors is an integer number (30589650).

Almost surely, 2^645406560 is an apocalyptic number.

645406560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

645406560 is an abundant number, since it is smaller than the sum of its proper divisors (1557048240).

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

645406560 is a wasteful number, since it uses less digits than its factorization.

645406560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448220 (or 448209 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 645406560 is about 25404.8530796775. The cubic root of 645406560 is about 864.1937579855.

The spelling of 645406560 in words is "six hundred forty-five million, four hundred six thousand, five hundred sixty".