21378638600 has 96 divisors (see below), whose sum is σ = 54549633600. Its totient is φ = 7727366400.

The previous prime is 21378638581. The next prime is 21378638629. The reversal of 21378638600 is 683687312.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 338306 + ... + 396494.

It is an arithmetic number, because the mean of its divisors is an integer number (568225350).

Almost surely, 2^21378638600 is an apocalyptic number.

21378638600 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 21378638600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27274816800).

21378638600 is an abundant number, since it is smaller than the sum of its proper divisors (33170995000).

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

21378638600 is a wasteful number, since it uses less digits than its factorization.

21378638600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58383 (or 58374 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The spelling of 21378638600 in words is "twenty-one billion, three hundred seventy-eight million, six hundred thirty-eight thousand, six hundred".