208749385861 has 2 divisors, whose sum is σ = 208749385862. Its totient is φ = 208749385860.

The previous prime is 208749385849. The next prime is 208749385891. The reversal of 208749385861 is 168583947802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160344985761 + 48404400100 = 400431^2 + 220010^2 .

It is a cyclic number.

It is not a de Polignac number, because 208749385861 - 2¹⁵ = 208749353093 is a prime.

It is a super-2 number, since 2×208749385861² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 208749385861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208749385811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104374692930 + 104374692931.

It is an arithmetic number, because the mean of its divisors is an integer number (104374692931).

It is a 1-persistent number, because it is pandigital, but 2⋅208749385861 = 417498771722 is not.

Almost surely, 2^208749385861 is an apocalyptic number.

It is an amenable number.

208749385861 is a deficient number, since it is larger than the sum of its proper divisors (1).

208749385861 is an equidigital number, since it uses as much as digits as its factorization.

208749385861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23224320, while the sum is 61.

The spelling of 208749385861 in words is "two hundred eight billion, seven hundred forty-nine million, three hundred eighty-five thousand, eight hundred sixty-one".