21001313100 has 72 divisors (see below), whose sum is σ = 60843484240. Its totient is φ = 5593006080.

The previous prime is 21001313057. The next prime is 21001313131. The reversal of 21001313100 is 131310012.

It is a super-2 number, since 2×21001313100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 185184 + ... + 276216.

Almost surely, 2^21001313100 is an apocalyptic number.

21001313100 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 21001313100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30421742120).

21001313100 is an abundant number, since it is smaller than the sum of its proper divisors (39842171140).

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

21001313100 is a wasteful number, since it uses less digits than its factorization.

21001313100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91819 (or 91812 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 12.

Adding to 21001313100 its reverse (131310012), we get a palindrome (21132623112).

The spelling of 21001313100 in words is "twenty-one billion, one million, three hundred thirteen thousand, one hundred".