640061 has 2 divisors, whose sum is σ = 640062. Its totient is φ = 640060.

The previous prime is 640049. The next prime is 640069. The reversal of 640061 is 160046.

640061 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 337561 + 302500 = 581^2 + 550^2 .

It is a cyclic number.

It is not a de Polignac number, because 640061 - 2⁶ = 639997 is a prime.

It is a Chen prime.

It is equal to p₅₂₀₈₂ and since 640061 and 52082 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640061.

It is not a weakly prime, because it can be changed into another prime (640069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320030 + 320031.

It is an arithmetic number, because the mean of its divisors is an integer number (320031).

2⁶⁴⁰⁰⁶¹ is an apocalyptic number.

It is an amenable number.

640061 is a deficient number, since it is larger than the sum of its proper divisors (1).

640061 is an equidigital number, since it uses as much as digits as its factorization.

640061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 640061 is about 800.0381240916. The cubic root of 640061 is about 86.1801254417.

The spelling of 640061 in words is "six hundred forty thousand, sixty-one".