21020102272 has 64 divisors (see below), whose sum is σ = 45132753960. Its totient is φ = 9693941760.

The previous prime is 21020102143. The next prime is 21020102273. The reversal of 21020102272 is 27220102012.

It can be written as a sum of positive squares in 4 ways, for example, as 20248151616 + 771950656 = 142296^2 + 27784^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (21020102273) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2480122 + ... + 2488582.

Almost surely, 2^21020102272 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020102272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22566376980).

21020102272 is an abundant number, since it is smaller than the sum of its proper divisors (24112651688).

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

21020102272 is a wasteful number, since it uses less digits than its factorization.

21020102272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9981 (or 9969 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 19.

Adding to 21020102272 its reverse (27220102012), we get a palindrome (48240204284).

The spelling of 21020102272 in words is "twenty-one billion, twenty million, one hundred two thousand, two hundred seventy-two".