21101310 has 80 divisors (see below), whose sum is σ = 57499200. Its totient is φ = 5552064.

The previous prime is 21101309. The next prime is 21101317. The reversal of 21101310 is 1310112.

It is a super-2 number, since 2×21101310² = 890530567432200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21101292 and 21101301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101317) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 88171 + ... + 88409.

It is an arithmetic number, because the mean of its divisors is an integer number (718740).

Almost surely, 2^21101310 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21101310, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28749600).

21101310 is an abundant number, since it is smaller than the sum of its proper divisors (36397890).

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

21101310 is a wasteful number, since it uses less digits than its factorization.

21101310 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367 (or 358 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

The square root of 21101310 is about 4593.6162225419. The cubic root of 21101310 is about 276.3353673776.

Adding to 21101310 its reverse (1310112), we get a palindrome (22411422).

The spelling of 21101310 in words is "twenty-one million, one hundred one thousand, three hundred ten".