19811896 has 32 divisors (see below), whose sum is σ = 40249440. Its totient is φ = 9088128.

The previous prime is 19811867. The next prime is 19811903. The reversal of 19811896 is 69811891.

It is a happy number.

It is a super-2 number, since 2×19811896² = 785022446229632, which contains 22 as substring.

It is a congruent number.

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, 20005 + ... + 20971.

It is an arithmetic number, because the mean of its divisors is an integer number (1257795).

Almost surely, 2^19811896 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 19811896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20124720).

19811896 is an abundant number, since it is smaller than the sum of its proper divisors (20437544).

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

19811896 is a wasteful number, since it uses less digits than its factorization.

19811896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183 (or 1179 counting only the distinct ones).

The product of its digits is 31104, while the sum is 43.

The square root of 19811896 is about 4451.0556051346. The cubic root of 19811896 is about 270.5880917083.

The spelling of 19811896 in words is "nineteen million, eight hundred eleven thousand, eight hundred ninety-six".