640938449970 has 1728 divisors, whose sum is σ = 2422341282816. Its totient is φ = 120630021120.

The previous prime is 640938449867. The next prime is 640938450017. The reversal of 640938449970 is 79944839046.

640938449970 is a `hidden beast` number, since 6 + 40 + 9 + 38 + 4 + 499 + 70 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 640938449898 and 640938449907.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 863 ways as a sum of consecutive naturals, for example, 17322660792 + ... + 17322660828.

It is an arithmetic number, because the mean of its divisors is an integer number (1401817872).

Almost surely, 2^640938449970 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640938449970, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1211170641408).

640938449970 is an abundant number, since it is smaller than the sum of its proper divisors (1781402832846).

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

640938449970 is a wasteful number, since it uses less digits than its factorization.

640938449970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 47029248, while the sum is 63.

The spelling of 640938449970 in words is "six hundred forty billion, nine hundred thirty-eight million, four hundred forty-nine thousand, nine hundred seventy".