19918312 has 8 divisors (see below), whose sum is σ = 37346850. Its totient is φ = 9959152.

The previous prime is 19918303. The next prime is 19918313. The reversal of 19918312 is 21381991.

It can be written as a sum of positive squares in only one way, i.e., 17589636 + 2328676 = 4194^2 + 1526^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (19918313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1244887 + ... + 1244902.

Almost surely, 2^19918312 is an apocalyptic number.

It is an amenable number.

19918312 is a deficient number, since it is larger than the sum of its proper divisors (17428538).

19918312 is a wasteful number, since it uses less digits than its factorization.

19918312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2489795 (or 2489791 counting only the distinct ones).

The product of its digits is 3888, while the sum is 34.

The square root of 19918312 is about 4462.9936141563. The cubic root of 19918312 is about 271.0716984621.

The spelling of 19918312 in words is "nineteen million, nine hundred eighteen thousand, three hundred twelve".