640533551240 has 64 divisors (see below), whose sum is σ = 1578020555520. Its totient is φ = 232061760000.

The previous prime is 640533551227. The next prime is 640533551269. The reversal of 640533551240 is 42155335046.

It is a junction number, because it is equal to n+sod(n) for n = 640533551194 and 640533551203.

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, 2566661 + ... + 2805140.

It is an arithmetic number, because the mean of its divisors is an integer number (24656571180).

Almost surely, 2^640533551240 is an apocalyptic number.

It is an amenable number.

640533551240 is an abundant number, since it is smaller than the sum of its proper divisors (937487004280).

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

640533551240 is a wasteful number, since it uses less digits than its factorization.

640533551240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5372094 (or 5372090 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 38.

Adding to 640533551240 its reverse (42155335046), we get a palindrome (682688886286).

The spelling of 640533551240 in words is "six hundred forty billion, five hundred thirty-three million, five hundred fifty-one thousand, two hundred forty".