645397280 has 48 divisors (see below), whose sum is σ = 1663369344. Its totient is φ = 234689280.

The previous prime is 645397267. The next prime is 645397321. The reversal of 645397280 is 82793546.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 181592 + ... + 185111.

It is an arithmetic number, because the mean of its divisors is an integer number (34653528).

Almost surely, 2^645397280 is an apocalyptic number.

It is an amenable number.

645397280 is an abundant number, since it is smaller than the sum of its proper divisors (1017972064).

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

645397280 is a wasteful number, since it uses less digits than its factorization.

645397280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366729 (or 366721 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 44.

The square root of 645397280 is about 25404.6704367524. The cubic root of 645397280 is about 864.1896160193.

The spelling of 645397280 in words is "six hundred forty-five million, three hundred ninety-seven thousand, two hundred eighty".