21172191336 has 96 divisors (see below), whose sum is σ = 58050969600. Its totient is φ = 6970561920.

The previous prime is 21172191331. The next prime is 21172191353. The reversal of 21172191336 is 63319127112.

21172191336 is a `hidden beast` number, since 211 + 7 + 21 + 91 + 336 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21172191336.

It is not an unprimeable number, because it can be changed into a prime (21172191331) 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, 2088921 + ... + 2099031.

It is an arithmetic number, because the mean of its divisors is an integer number (604697600).

Almost surely, 2^21172191336 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 21172191336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29025484800).

21172191336 is an abundant number, since it is smaller than the sum of its proper divisors (36878778264).

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

21172191336 is a wasteful number, since it uses less digits than its factorization.

21172191336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10479 (or 10472 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The spelling of 21172191336 in words is "twenty-one billion, one hundred seventy-two million, one hundred ninety-one thousand, three hundred thirty-six".