209073978 has 12 divisors (see below), whose sum is σ = 452993658. Its totient is φ = 69691320.

The previous prime is 209073947. The next prime is 209073983. The reversal of 209073978 is 879370902.

It can be written as a sum of positive squares in only one way, i.e., 182169009 + 26904969 = 13497^2 + 5187^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5807593 + ... + 5807628.

Almost surely, 2^209073978 is an apocalyptic number.

209073978 is an abundant number, since it is smaller than the sum of its proper divisors (243919680).

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

209073978 is a wasteful number, since it uses less digits than its factorization.

209073978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11615229 (or 11615226 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 209073978 is about 14459.3906510613. The cubic root of 209073978 is about 593.5172249796.

The spelling of 209073978 in words is "two hundred nine million, seventy-three thousand, nine hundred seventy-eight".