21101308281 has 12 divisors (see below), whose sum is σ = 30583697508. Its totient is φ = 14019525024.

The previous prime is 21101308271. The next prime is 21101308289. The reversal of 21101308281 is 18280310112.

It can be written as a sum of positive squares in 2 ways, for example, as 10463448681 + 10637859600 = 102291^2 + 103140^2 .

It is not a de Polignac number, because 21101308281 - 2¹⁰ = 21101307257 is a prime.

It is a super-2 number, since 2×21101308281² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21101308289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3998370 + ... + 4003643.

It is an arithmetic number, because the mean of its divisors is an integer number (2548641459).

Almost surely, 2^21101308281 is an apocalyptic number.

It is an amenable number.

21101308281 is a deficient number, since it is larger than the sum of its proper divisors (9482389227).

21101308281 is a wasteful number, since it uses less digits than its factorization.

21101308281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8002312 (or 8002309 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

Adding to 21101308281 its reverse (18280310112), we get a palindrome (39381618393).

The spelling of 21101308281 in words is "twenty-one billion, one hundred one million, three hundred eight thousand, two hundred eighty-one".