208749385881 has 9 divisors (see below), whose sum is σ = 301528870591. Its totient is φ = 139165343472.

The previous prime is 208749385861. The next prime is 208749385891. The reversal of 208749385881 is 188583947802.

The square root of 208749385881 is 456891.

It is a perfect power (a square), and thus also a powerful number.

208749385881 is a `hidden beast` number, since 2 + 0 + 8 + 7 + 49 + 3 + 8 + 588 + 1 = 666.

208749385881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 20233640025 + 188515745856 = 142245^2 + 434184^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 208749385881 - 2⁵ = 208749385849 is a prime.

It is a super-2 number, since 2×208749385881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (208749385811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1294525 + ... + 1446821.

Almost surely, 2^208749385881 is an apocalyptic number.

208749385881 is the 456891-st square number.

208749385881 is the 228446-th centered octagonal number.

It is an amenable number.

208749385881 is a deficient number, since it is larger than the sum of its proper divisors (92779484710).

208749385881 is an frugal number, since it uses more digits than its factorization.

208749385881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304600 (or 152300 counting only the distinct ones).

The product of its (nonzero) digits is 30965760, while the sum is 63.

The spelling of 208749385881 in words is "two hundred eight billion, seven hundred forty-nine million, three hundred eighty-five thousand, eight hundred eighty-one".