21004175718 has 128 divisors (see below), whose sum is σ = 48184012800. Its totient is φ = 6780174336.

The previous prime is 21004175711. The next prime is 21004175743. The reversal of 21004175718 is 81757140012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004175711) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 79863655 + ... + 79863917.

It is an arithmetic number, because the mean of its divisors is an integer number (376437600).

Almost surely, 2^21004175718 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21004175718, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24092006400).

21004175718 is an abundant number, since it is smaller than the sum of its proper divisors (27179837082).

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

21004175718 is a wasteful number, since it uses less digits than its factorization.

21004175718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643 (or 637 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 36.

The spelling of 21004175718 in words is "twenty-one billion, four million, one hundred seventy-five thousand, seven hundred eighteen".