21905100000 has 1152 divisors, whose sum is σ = 97643750400. Its totient is φ = 4665600000.

The previous prime is 21905099977. The next prime is 21905100011. The reversal of 21905100000 is 150912.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 359099970 + ... + 359100030.

It is an arithmetic number, because the mean of its divisors is an integer number (84760200).

Almost surely, 2^21905100000 is an apocalyptic number.

21905100000 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 21905100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48821875200).

21905100000 is an abundant number, since it is smaller than the sum of its proper divisors (75738650400).

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

21905100000 is an equidigital number, since it uses as much as digits as its factorization.

21905100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

Adding to 21905100000 its reverse (150912), we get a palindrome (21905250912).

The spelling of 21905100000 in words is "twenty-one billion, nine hundred five million, one hundred thousand".