640621103550 has 48 divisors (see below), whose sum is σ = 1588890291120. Its totient is φ = 170816170240.

The previous prime is 640621103533. The next prime is 640621103561. The reversal of 640621103550 is 55301126046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1437244 + ... + 1829456.

It is an arithmetic number, because the mean of its divisors is an integer number (33101881065).

Almost surely, 2^640621103550 is an apocalyptic number.

640621103550 is an abundant number, since it is smaller than the sum of its proper divisors (948269187570).

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

640621103550 is a wasteful number, since it uses less digits than its factorization.

640621103550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403117 (or 403112 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

Adding to 640621103550 its reverse (55301126046), we get a palindrome (695922229596).

The spelling of 640621103550 in words is "six hundred forty billion, six hundred twenty-one million, one hundred three thousand, five hundred fifty".