640435232400 has 120 divisors (see below), whose sum is σ = 2054633745024. Its totient is φ = 170524147200.

The previous prime is 640435232389. The next prime is 640435232401. The reversal of 640435232400 is 4232534046.

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

It is not an unprimeable number, because it can be changed into a prime (640435232401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 389497 + ... + 1196903.

Almost surely, 2^640435232400 is an apocalyptic number.

640435232400 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 640435232400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1027316872512).

640435232400 is an abundant number, since it is smaller than the sum of its proper divisors (1414198512624).

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

640435232400 is a wasteful number, since it uses less digits than its factorization.

640435232400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 808089 (or 808078 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 33.

Adding to 640435232400 its reverse (4232534046), we get a palindrome (644667766446).

The spelling of 640435232400 in words is "six hundred forty billion, four hundred thirty-five million, two hundred thirty-two thousand, four hundred".