809231978 has 16 divisors (see below), whose sum is σ = 1235311560. Its totient is φ = 397478400.

The previous prime is 809231957. The next prime is 809231981. The reversal of 809231978 is 879132908.

It can be written as a sum of positive squares in 4 ways, for example, as 267878689 + 541353289 = 16367^2 + 23267^2 .

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, 103718 + ... + 111246.

Almost surely, 2^809231978 is an apocalyptic number.

809231978 is a deficient number, since it is larger than the sum of its proper divisors (426079582).

809231978 is a wasteful number, since it uses less digits than its factorization.

809231978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8473.

The product of its (nonzero) digits is 217728, while the sum is 47.

The square root of 809231978 is about 28447.0029704361. The cubic root of 809231978 is about 931.8750385059.

The spelling of 809231978 in words is "eight hundred nine million, two hundred thirty-one thousand, nine hundred seventy-eight".