21355551100 has 144 divisors (see below), whose sum is σ = 51642694656. Its totient is φ = 7614720000.

The previous prime is 21355551071. The next prime is 21355551101. The reversal of 21355551100 is 115555312.

It is a super-2 number, since 2×21355551100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355551101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5381317 + ... + 5385283.

It is an arithmetic number, because the mean of its divisors is an integer number (358629824).

Almost surely, 2^21355551100 is an apocalyptic number.

21355551100 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 21355551100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25821347328).

21355551100 is an abundant number, since it is smaller than the sum of its proper divisors (30287143556).

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

21355551100 is a wasteful number, since it uses less digits than its factorization.

21355551100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4136 (or 4129 counting only the distinct ones).

The product of its (nonzero) digits is 3750, while the sum is 28.

The spelling of 21355551100 in words is "twenty-one billion, three hundred fifty-five million, five hundred fifty-one thousand, one hundred".