208220666 has 4 divisors (see below), whose sum is σ = 312331002. Its totient is φ = 104110332.

The previous prime is 208220651. The next prime is 208220671. The reversal of 208220666 is 666022802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666022802 = 2 ⋅333011401.

It can be written as a sum of positive squares in only one way, i.e., 172160641 + 36060025 = 13121^2 + 6005^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52055165 + ... + 52055168.

Almost surely, 2^208220666 is an apocalyptic number.

208220666 is a deficient number, since it is larger than the sum of its proper divisors (104110336).

208220666 is a wasteful number, since it uses less digits than its factorization.

208220666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104110335.

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 208220666 is about 14429.8532910075. The cubic root of 208220666 is about 592.7086659625.

The spelling of 208220666 in words is "two hundred eight million, two hundred twenty thousand, six hundred sixty-six".