645431000 has 32 divisors (see below), whose sum is σ = 1510310880. Its totient is φ = 258172000.

The previous prime is 645430999. The next prime is 645431041. The reversal of 645431000 is 134546.

It is a happy number.

It is a super-2 number, since 2×645431000² = 833162351522000000, which contains 22 as substring.

It is a congruent number.

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, 321716 + ... + 323715.

It is an arithmetic number, because the mean of its divisors is an integer number (47197215).

Almost surely, 2^645431000 is an apocalyptic number.

It is an amenable number.

645431000 is an abundant number, since it is smaller than the sum of its proper divisors (864879880).

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

645431000 is a wasteful number, since it uses less digits than its factorization.

645431000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645452 (or 645438 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 645431000 is about 25405.3340855813. The cubic root of 645431000 is about 864.2046661635.

Adding to 645431000 its reverse (134546), we get a palindrome (645565546).

The spelling of 645431000 in words is "six hundred forty-five million, four hundred thirty-one thousand".