645390000 has 300 divisors, whose sum is σ = 2311472592. Its totient is φ = 168000000.

The previous prime is 645389977. The next prime is 645390017. The reversal of 645390000 is 93546.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (300).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 6389950 + ... + 6390050.

Almost surely, 2^645390000 is an apocalyptic number.

645390000 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 645390000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1155736296).

645390000 is an abundant number, since it is smaller than the sum of its proper divisors (1666082592).

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

645390000 is a wasteful number, since it uses less digits than its factorization.

645390000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 182 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 645390000 is about 25404.5271556075. The cubic root of 645390000 is about 864.1863666904.

The spelling of 645390000 in words is "six hundred forty-five million, three hundred ninety thousand".