21013131210 has 64 divisors (see below), whose sum is σ = 51690469248. Its totient is φ = 5464053504.

The previous prime is 21013131203. The next prime is 21013131229. The reversal of 21013131210 is 1213131012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21013131210.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 777484 + ... + 804056.

It is an arithmetic number, because the mean of its divisors is an integer number (807663582).

Almost surely, 2^21013131210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21013131210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25845234624).

21013131210 is an abundant number, since it is smaller than the sum of its proper divisors (30677338038).

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

21013131210 is a wasteful number, since it uses less digits than its factorization.

21013131210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27239.

The product of its (nonzero) digits is 36, while the sum is 15.

Adding to 21013131210 its reverse (1213131012), we get a palindrome (22226262222).

The spelling of 21013131210 in words is "twenty-one billion, thirteen million, one hundred thirty-one thousand, two hundred ten".