208400818 has 4 divisors (see below), whose sum is σ = 312601230. Its totient is φ = 104200408.

The previous prime is 208400809. The next prime is 208400831. The reversal of 208400818 is 818004802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 818004802 = 2 ⋅409002401.

It can be written as a sum of positive squares in only one way, i.e., 177342489 + 31058329 = 13317^2 + 5573^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 208400818.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52100203 + ... + 52100206.

Almost surely, 2^208400818 is an apocalyptic number.

208400818 is a deficient number, since it is larger than the sum of its proper divisors (104200412).

208400818 is a wasteful number, since it uses less digits than its factorization.

208400818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104200411.

The product of its (nonzero) digits is 4096, while the sum is 31.

The square root of 208400818 is about 14436.0942778856. The cubic root of 208400818 is about 592.8795533739.

The spelling of 208400818 in words is "two hundred eight million, four hundred thousand, eight hundred eighteen".