208187320891 has 12 divisors (see below), whose sum is σ = 228848464152. Its totient is φ = 189249236000.

The previous prime is 208187320883. The next prime is 208187320937. The reversal of 208187320891 is 198023781802.

It is not a de Polignac number, because 208187320891 - 2³ = 208187320883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (208187320871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2279751 + ... + 2369311.

It is an arithmetic number, because the mean of its divisors is an integer number (19070705346).

Almost surely, 2^208187320891 is an apocalyptic number.

208187320891 is a deficient number, since it is larger than the sum of its proper divisors (20661143261).

208187320891 is a wasteful number, since it uses less digits than its factorization.

208187320891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108794 (or 108783 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 49.

The spelling of 208187320891 in words is "two hundred eight billion, one hundred eighty-seven million, three hundred twenty thousand, eight hundred ninety-one".