309991048 has 16 divisors (see below), whose sum is σ = 587226780. Its totient is φ = 153397248.

The previous prime is 309991043. The next prime is 309991057. The reversal of 309991048 is 840199903.

It can be written as a sum of positive squares in 2 ways, for example, as 272316004 + 37675044 = 16502^2 + 6138^2 .

It is a junction number, because it is equal to n+sod(n) for n = 309990995 and 309991013.

It is not an unprimeable number, because it can be changed into a prime (309991043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198961 + ... + 200512.

Almost surely, 2^309991048 is an apocalyptic number.

It is an amenable number.

309991048 is a deficient number, since it is larger than the sum of its proper divisors (277235732).

309991048 is a wasteful number, since it uses less digits than its factorization.

309991048 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399576 (or 399572 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 309991048 is about 17606.5626401067. The cubic root of 309991048 is about 676.7834304990.

The spelling of 309991048 in words is "three hundred nine million, nine hundred ninety-one thousand, forty-eight".