21210531100 has 144 divisors (see below), whose sum is σ = 54170345376. Its totient is φ = 7121920000.

The previous prime is 21210531071. The next prime is 21210531113. The reversal of 21210531100 is 113501212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 980400 + ... + 1001800.

It is an arithmetic number, because the mean of its divisors is an integer number (376182954).

Almost surely, 2^21210531100 is an apocalyptic number.

21210531100 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 21210531100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27085172688).

21210531100 is an abundant number, since it is smaller than the sum of its proper divisors (32959814276).

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

21210531100 is a wasteful number, since it uses less digits than its factorization.

21210531100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21496 (or 21489 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 16.

The spelling of 21210531100 in words is "twenty-one billion, two hundred ten million, five hundred thirty-one thousand, one hundred".