640454505812 has 48 divisors (see below), whose sum is σ = 1231167168000. Its totient is φ = 289097208960.

The previous prime is 640454505797. The next prime is 640454505841. The reversal of 640454505812 is 218505454046.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41091773 + ... + 41107355.

It is an arithmetic number, because the mean of its divisors is an integer number (25649316000).

Almost surely, 2^640454505812 is an apocalyptic number.

It is an amenable number.

640454505812 is a deficient number, since it is larger than the sum of its proper divisors (590712662188).

640454505812 is a wasteful number, since it uses less digits than its factorization.

640454505812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22016 (or 22014 counting only the distinct ones).

The product of its (nonzero) digits is 768000, while the sum is 44.

Adding to 640454505812 its reverse (218505454046), we get a palindrome (858959959858).

The spelling of 640454505812 in words is "six hundred forty billion, four hundred fifty-four million, five hundred five thousand, eight hundred twelve".