640545242185061 has 2 divisors, whose sum is σ = 640545242185062. Its totient is φ = 640545242185060.

The previous prime is 640545242185039. The next prime is 640545242185067. The reversal of 640545242185061 is 160581242545046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 639700692213025 + 844549972036 = 25292305^2 + 918994^2 .

It is a cyclic number.

It is not a de Polignac number, because 640545242185061 - 2⁶ = 640545242184997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640545242184994 and 640545242185012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640545242185067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320272621092530 + 320272621092531.

It is an arithmetic number, because the mean of its divisors is an integer number (320272621092531).

Almost surely, 2^{640545242185061} is an apocalyptic number.

It is an amenable number.

640545242185061 is a deficient number, since it is larger than the sum of its proper divisors (1).

640545242185061 is an equidigital number, since it uses as much as digits as its factorization.

640545242185061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216000, while the sum is 53.

The spelling of 640545242185061 in words is "six hundred forty trillion, five hundred forty-five billion, two hundred forty-two million, one hundred eighty-five thousand, sixty-one".