21213545100 has 144 divisors (see below), whose sum is σ = 67621671936. Its totient is φ = 5091680000.

The previous prime is 21213545069. The next prime is 21213545107. The reversal of 21213545100 is 154531212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21213545107) 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, 301477 + ... + 365123.

It is an arithmetic number, because the mean of its divisors is an integer number (469594944).

Almost surely, 2^21213545100 is an apocalyptic number.

21213545100 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 21213545100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33810835968).

21213545100 is an abundant number, since it is smaller than the sum of its proper divisors (46408126836).

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

21213545100 is a wasteful number, since it uses less digits than its factorization.

21213545100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63776 (or 63769 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The spelling of 21213545100 in words is "twenty-one billion, two hundred thirteen million, five hundred forty-five thousand, one hundred".