640506061 has 16 divisors (see below), whose sum is σ = 695858688. Its totient is φ = 586051200.

The previous prime is 640506019. The next prime is 640506079. The reversal of 640506061 is 160605046.

640506061 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 640506061 - 2⁷ = 640505933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640506011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 989640 + ... + 990286.

It is an arithmetic number, because the mean of its divisors is an integer number (43491168).

Almost surely, 2^640506061 is an apocalyptic number.

It is an amenable number.

640506061 is a deficient number, since it is larger than the sum of its proper divisors (55352627).

640506061 is a wasteful number, since it uses less digits than its factorization.

640506061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 640506061 is about 25308.2212136689. The cubic root of 640506061 is about 862.0009568736. Note that the first 3 decimals are identical.

The spelling of 640506061 in words is "six hundred forty million, five hundred six thousand, sixty-one".