205720513643 has 2 divisors, whose sum is σ = 205720513644. Its totient is φ = 205720513642.

The previous prime is 205720513639. The next prime is 205720513697. The reversal of 205720513643 is 346315027502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 205720513643 - 2² = 205720513639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205720513597 and 205720513606.

It is not a weakly prime, because it can be changed into another prime (205720513043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102860256821 + 102860256822.

It is an arithmetic number, because the mean of its divisors is an integer number (102860256822).

Almost surely, 2^205720513643 is an apocalyptic number.

205720513643 is a deficient number, since it is larger than the sum of its proper divisors (1).

205720513643 is an equidigital number, since it uses as much as digits as its factorization.

205720513643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151200, while the sum is 38.

The spelling of 205720513643 in words is "two hundred five billion, seven hundred twenty million, five hundred thirteen thousand, six hundred forty-three".