21178828800 has 864 divisors, whose sum is σ = 83174364000. Its totient is φ = 5131468800.

The previous prime is 21178828799. The next prime is 21178828807. The reversal of 21178828800 is 882887112.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21178828807) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 358963171 + ... + 358963229.

It is an arithmetic number, because the mean of its divisors is an integer number (96266625).

Almost surely, 2^21178828800 is an apocalyptic number.

21178828800 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 21178828800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41587182000).

21178828800 is an abundant number, since it is smaller than the sum of its proper divisors (61995535200).

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

21178828800 is a wasteful number, since it uses less digits than its factorization.

21178828800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 114688, while the sum is 45.

The spelling of 21178828800 in words is "twenty-one billion, one hundred seventy-eight million, eight hundred twenty-eight thousand, eight hundred".