19971318 has 32 divisors (see below), whose sum is σ = 42278400. Its totient is φ = 6271776.

The previous prime is 19971313. The next prime is 19971349. The reversal of 19971318 is 81317991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19971313) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26880 + ... + 27612.

It is an arithmetic number, because the mean of its divisors is an integer number (1321200).

Almost surely, 2^19971318 is an apocalyptic number.

19971318 is an abundant number, since it is smaller than the sum of its proper divisors (22307082).

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

19971318 is a wasteful number, since it uses less digits than its factorization.

19971318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 996.

The product of its digits is 13608, while the sum is 39.

The square root of 19971318 is about 4468.9280593896. The cubic root of 19971318 is about 271.3119413711.

It can be divided in two parts, 199 and 71318, that added together give a palindrome (71517).

The spelling of 19971318 in words is "nineteen million, nine hundred seventy-one thousand, three hundred eighteen".