21131228160 has 880 divisors, whose sum is σ = 89880658560. Its totient is φ = 4644864000.

The previous prime is 21131228159. The next prime is 21131228171. The reversal of 21131228160 is 6182213112.

21131228160 is a `hidden beast` number, since 2 + 11 + 312 + 281 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 84188035 + ... + 84188285.

It is an arithmetic number, because the mean of its divisors is an integer number (102137112).

Almost surely, 2^21131228160 is an apocalyptic number.

21131228160 is a gapful number since it is divisible by the number (20) 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 21131228160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44940329280).

21131228160 is an abundant number, since it is smaller than the sum of its proper divisors (68749430400).

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

21131228160 is a wasteful number, since it uses less digits than its factorization.

21131228160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The spelling of 21131228160 in words is "twenty-one billion, one hundred thirty-one million, two hundred twenty-eight thousand, one hundred sixty".