21011320231 has 16 divisors (see below), whose sum is σ = 23180048640. Its totient is φ = 18886510720.

The previous prime is 21011320229. The next prime is 21011320243. The reversal of 21011320231 is 13202311012.

It is not a de Polignac number, because 21011320231 - 2¹ = 21011320229 is a prime.

It is a super-2 number, since 2×21011320231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011320261) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 500646 + ... + 540988.

It is an arithmetic number, because the mean of its divisors is an integer number (1448753040).

Almost surely, 2^21011320231 is an apocalyptic number.

21011320231 is a deficient number, since it is larger than the sum of its proper divisors (2168728409).

21011320231 is a wasteful number, since it uses less digits than its factorization.

21011320231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40886.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21011320231 its reverse (13202311012), we get a palindrome (34213631243).

The spelling of 21011320231 in words is "twenty-one billion, eleven million, three hundred twenty thousand, two hundred thirty-one".