208445561 has 4 divisors (see below), whose sum is σ = 219416400. Its totient is φ = 197474724.

The previous prime is 208445557. The next prime is 208445579. The reversal of 208445561 is 165544802.

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 208445561 - 2² = 208445557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (208441561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5485391 + ... + 5485428.

It is an arithmetic number, because the mean of its divisors is an integer number (54854100).

Almost surely, 2^208445561 is an apocalyptic number.

It is an amenable number.

208445561 is a deficient number, since it is larger than the sum of its proper divisors (10970839).

208445561 is a wasteful number, since it uses less digits than its factorization.

208445561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10970838.

The product of its (nonzero) digits is 38400, while the sum is 35.

The square root of 208445561 is about 14437.6438867289. The cubic root of 208445561 is about 592.9219801294.

The spelling of 208445561 in words is "two hundred eight million, four hundred forty-five thousand, five hundred sixty-one".