645393280 has 64 divisors (see below), whose sum is σ = 1763318880. Its totient is φ = 221276160.

The previous prime is 645393211. The next prime is 645393293. The reversal of 645393280 is 82393546.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67551 + ... + 76510.

Almost surely, 2^645393280 is an apocalyptic number.

It is an amenable number.

645393280 is an abundant number, since it is smaller than the sum of its proper divisors (1117925600).

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

645393280 is a wasteful number, since it uses less digits than its factorization.

645393280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144087 (or 144075 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 645393280 is about 25404.5917109486. The cubic root of 645393280 is about 864.1878306768.

The spelling of 645393280 in words is "six hundred forty-five million, three hundred ninety-three thousand, two hundred eighty".