645404000 has 96 divisors (see below), whose sum is σ = 1619968896. Its totient is φ = 252595200.

The previous prime is 645403999. The next prime is 645404021. The reversal of 645404000 is 404546.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 186284 + ... + 189716.

It is an arithmetic number, because the mean of its divisors is an integer number (16874676).

Almost surely, 2^645404000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645404000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (809984448).

645404000 is an abundant number, since it is smaller than the sum of its proper divisors (974564896).

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

645404000 is a wasteful number, since it uses less digits than its factorization.

645404000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3505 (or 3487 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 645404000 is about 25404.8026955535. The cubic root of 645404000 is about 864.1926153781.

Adding to 645404000 its reverse (404546), we get a palindrome (645808546).

The spelling of 645404000 in words is "six hundred forty-five million, four hundred four thousand".