645462720 has 336 divisors, whose sum is σ = 2570488128. Its totient is φ = 145612800.

The previous prime is 645462709. The next prime is 645462751. The reversal of 645462720 is 27264546.

645462720 is a `hidden beast` number, since 6 + 4 + 5 + 4 + 627 + 20 = 666.

645462720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2036002 + ... + 2036318.

Almost surely, 2^645462720 is an apocalyptic number.

645462720 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 645462720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1285244064).

645462720 is an abundant number, since it is smaller than the sum of its proper divisors (1925025408).

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

645462720 is a wasteful number, since it uses less digits than its factorization.

645462720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448 (or 435 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 645462720 is about 25405.9583562597. The cubic root of 645462720 is about 864.2188231753.

The spelling of 645462720 in words is "six hundred forty-five million, four hundred sixty-two thousand, seven hundred twenty".