640460400 has 120 divisors (see below), whose sum is σ = 2057677824. Its totient is φ = 170284800.

The previous prime is 640460371. The next prime is 640460407. The reversal of 640460400 is 4064046.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640460407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 588657 + ... + 589743.

Almost surely, 2^640460400 is an apocalyptic number.

640460400 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 640460400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028838912).

640460400 is an abundant number, since it is smaller than the sum of its proper divisors (1417217424).

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

640460400 is a wasteful number, since it uses less digits than its factorization.

640460400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1599 (or 1588 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 640460400 is about 25307.3190994226. The cubic root of 640460400 is about 861.9804726745.

The spelling of 640460400 in words is "six hundred forty million, four hundred sixty thousand, four hundred".