640928336400 has 405 divisors, whose sum is σ = 2446798262727. Its totient is φ = 155248473600.

The previous prime is 640928336341. The next prime is 640928336401. The reversal of 640928336400 is 4633829046.

The square root of 640928336400 is 800580.

It is a perfect power (a square), and thus also a powerful number.

640928336400 is a `hidden beast` number, since 6 + 4 + 0 + 9 + 283 + 364 + 0 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 281158699536 + 359769636864 = 530244^2 + 599808^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (640928336401) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 528382194 + ... + 528383406.

Almost surely, 2^640928336400 is an apocalyptic number.

640928336400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

640928336400 is the 800580-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640928336400

640928336400 is an abundant number, since it is smaller than the sum of its proper divisors (1805869926327).

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

640928336400 is a wasteful number, since it uses less digits than its factorization.

640928336400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2472 (or 1234 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The spelling of 640928336400 in words is "six hundred forty billion, nine hundred twenty-eight million, three hundred thirty-six thousand, four hundred".