19981236 has 96 divisors (see below), whose sum is σ = 55480320. Its totient is φ = 5529600.

The previous prime is 19981231. The next prime is 19981243. The reversal of 19981236 is 63218991.

It is a junction number, because it is equal to n+sod(n) for n = 19981194 and 19981203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19981231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77620 + ... + 77876.

It is an arithmetic number, because the mean of its divisors is an integer number (577920).

Almost surely, 2^19981236 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19981236, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27740160).

19981236 is an abundant number, since it is smaller than the sum of its proper divisors (35499084).

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

19981236 is a wasteful number, since it uses less digits than its factorization.

19981236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325 (or 323 counting only the distinct ones).

The product of its digits is 23328, while the sum is 39.

The square root of 19981236 is about 4470.0375837346. The cubic root of 19981236 is about 271.3568462111.

The spelling of 19981236 in words is "nineteen million, nine hundred eighty-one thousand, two hundred thirty-six".