646405000 has 40 divisors (see below), whose sum is σ = 1514538630. Its totient is φ = 258560000.

The previous prime is 646404977. The next prime is 646405007. The reversal of 646405000 is 504646.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 120253156 + 526151844 = 10966^2 + 22938^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (646405007) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 59641 + ... + 69640.

Almost surely, 2^646405000 is an apocalyptic number.

It is an amenable number.

646405000 is an abundant number, since it is smaller than the sum of its proper divisors (868133630).

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

646405000 is a wasteful number, since it uses less digits than its factorization.

646405000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129307 (or 129288 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 646405000 is about 25424.4960618692. The cubic root of 646405000 is about 864.6391625373.

Adding to 646405000 its reverse (504646), we get a palindrome (646909646).

The spelling of 646405000 in words is "six hundred forty-six million, four hundred five thousand".