209968978 has 16 divisors (see below), whose sum is σ = 332346240. Its totient is φ = 99289696.

The previous prime is 209968949. The next prime is 209969003. The reversal of 209968978 is 879869902.

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, 21550 + ... + 29737.

It is an arithmetic number, because the mean of its divisors is an integer number (20771640).

Almost surely, 2^209968978 is an apocalyptic number.

209968978 is a deficient number, since it is larger than the sum of its proper divisors (122377262).

209968978 is a wasteful number, since it uses less digits than its factorization.

209968978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51401.

The product of its (nonzero) digits is 3919104, while the sum is 58.

The square root of 209968978 is about 14490.3063459680. The cubic root of 209968978 is about 594.3629252085.

The spelling of 209968978 in words is "two hundred nine million, nine hundred sixty-eight thousand, nine hundred seventy-eight".