208918906506 has 16 divisors (see below), whose sum is σ = 464264236800. Its totient is φ = 69639635484.

The previous prime is 208918906489. The next prime is 208918906519. The reversal of 208918906506 is 605609819802.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54), and also a Moran number because the ratio is a prime number: 3868868639 = 208918906506 / (2 + 0 + 8 + 9 + 1 + 8 + 9 + 0 + 6 + 5 + 0 + 6).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1934434266 + ... + 1934434373.

It is an arithmetic number, because the mean of its divisors is an integer number (29016514800).

Almost surely, 2^208918906506 is an apocalyptic number.

208918906506 is an abundant number, since it is smaller than the sum of its proper divisors (255345330294).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

208918906506 is a wasteful number, since it uses less digits than its factorization.

208918906506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3868868650 (or 3868868644 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 208918906506 in words is "two hundred eight billion, nine hundred eighteen million, nine hundred six thousand, five hundred six".