21488171904 has 576 divisors, whose sum is σ = 71646432000. Its totient is φ = 6159089664.

The previous prime is 21488171897. The next prime is 21488171917. The reversal of 21488171904 is 40917188412.

It is a tau number, because it is divible by the number of its divisors (576).

It is a self number, because there is not a number n which added to its sum of digits gives 21488171904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 272002137 + ... + 272002215.

Almost surely, 2^21488171904 is an apocalyptic number.

21488171904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21488171904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35823216000).

21488171904 is an abundant number, since it is smaller than the sum of its proper divisors (50158260096).

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

21488171904 is a wasteful number, since it uses less digits than its factorization.

21488171904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 21488171904 in words is "twenty-one billion, four hundred eighty-eight million, one hundred seventy-one thousand, nine hundred four".