21191611896 has 96 divisors (see below), whose sum is σ = 70638728160. Its totient is φ = 5588994816.

The previous prime is 21191611891. The next prime is 21191611921. The reversal of 21191611896 is 69811619112.

21191611896 is a `hidden beast` number, since 21 + 1 + 9 + 1 + 611 + 8 + 9 + 6 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21191611891) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1610635 + ... + 1623738.

It is an arithmetic number, because the mean of its divisors is an integer number (735820085).

Almost surely, 2^21191611896 is an apocalyptic number.

21191611896 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21191611896 is an abundant number, since it is smaller than the sum of its proper divisors (49447116264).

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

21191611896 is a wasteful number, since it uses less digits than its factorization.

21191611896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3234405 (or 3234398 counting only the distinct ones).

The product of its digits is 46656, while the sum is 45.

The spelling of 21191611896 in words is "twenty-one billion, one hundred ninety-one million, six hundred eleven thousand, eight hundred ninety-six".