208012318859521 has 4 divisors (see below), whose sum is σ = 226922529664944. Its totient is φ = 189102108054100.

The previous prime is 208012318859519. The next prime is 208012318859567. The reversal of 208012318859521 is 125958813210802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 208012318859521 - 2¹ = 208012318859519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (208012318859581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9455105402695 + ... + 9455105402716.

It is an arithmetic number, because the mean of its divisors is an integer number (56730632416236).

Almost surely, 2^{208012318859521} is an apocalyptic number.

It is an amenable number.

208012318859521 is a deficient number, since it is larger than the sum of its proper divisors (18910210805423).

208012318859521 is a wasteful number, since it uses less digits than its factorization.

208012318859521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18910210805422.

The product of its (nonzero) digits is 2764800, while the sum is 55.

The spelling of 208012318859521 in words is "two hundred eight trillion, twelve billion, three hundred eighteen million, eight hundred fifty-nine thousand, five hundred twenty-one".