640067540 has 48 divisors (see below), whose sum is σ = 1585726464. Its totient is φ = 212371200.

The previous prime is 640067507. The next prime is 640067557. The reversal of 640067540 is 45760046.

640067540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 640067497 and 640067506.

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, 69401 + ... + 78080.

It is an arithmetic number, because the mean of its divisors is an integer number (33035968).

Almost surely, 2^640067540 is an apocalyptic number.

It is an amenable number.

640067540 is an abundant number, since it is smaller than the sum of its proper divisors (945658924).

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

640067540 is a wasteful number, since it uses less digits than its factorization.

640067540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147528 (or 147526 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 32.

The square root of 640067540 is about 25299.5561225884. The cubic root of 640067540 is about 861.8041896379.

The spelling of 640067540 in words is "six hundred forty million, sixty-seven thousand, five hundred forty".