21171423708 has 96 divisors (see below), whose sum is σ = 56606760000. Its totient is φ = 6838594560.

The previous prime is 21171423703. The next prime is 21171423751. The reversal of 21171423708 is 80732417112.

21171423708 is a `hidden beast` number, since 211 + 71 + 4 + 2 + 370 + 8 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21171423703) 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, 643728 + ... + 675816.

It is an arithmetic number, because the mean of its divisors is an integer number (589653750).

Almost surely, 2^21171423708 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 21171423708, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28303380000).

21171423708 is an abundant number, since it is smaller than the sum of its proper divisors (35435336292).

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

21171423708 is a wasteful number, since it uses less digits than its factorization.

21171423708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32292 (or 32284 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The spelling of 21171423708 in words is "twenty-one billion, one hundred seventy-one million, four hundred twenty-three thousand, seven hundred eight".