208989978 has 16 divisors (see below), whose sum is σ = 422677440. Its totient is φ = 68880416.

The previous prime is 208989973. The next prime is 208990031. The reversal of 208989978 is 879989802.

It is not an unprimeable number, because it can be changed into a prime (208989973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195150 + ... + 196217.

It is an arithmetic number, because the mean of its divisors is an integer number (26417340).

Almost surely, 2^208989978 is an apocalyptic number.

208989978 is an abundant number, since it is smaller than the sum of its proper divisors (213687462).

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

208989978 is a wasteful number, since it uses less digits than its factorization.

208989978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391461.

The product of its (nonzero) digits is 5225472, while the sum is 60.

The square root of 208989978 is about 14456.4856725277. The cubic root of 208989978 is about 593.4377281978.

It can be divided in two parts, 20898 and 9978, that added together give a triangular number (30876 = T₂₄₈).

The spelling of 208989978 in words is "two hundred eight million, nine hundred eighty-nine thousand, nine hundred seventy-eight".