21641211231 has 4 divisors (see below), whose sum is σ = 28854948312. Its totient is φ = 14427474152.

The previous prime is 21641211217. The next prime is 21641211281. The reversal of 21641211231 is 13211214612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21641211231 - 2¹⁴ = 21641194847 is a prime.

It is a super-2 number, since 2×21641211231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641211281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3606868536 + ... + 3606868541.

It is an arithmetic number, because the mean of its divisors is an integer number (7213737078).

Almost surely, 2^21641211231 is an apocalyptic number.

21641211231 is a deficient number, since it is larger than the sum of its proper divisors (7213737081).

21641211231 is an equidigital number, since it uses as much as digits as its factorization.

21641211231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7213737080.

The product of its digits is 576, while the sum is 24.

Adding to 21641211231 its reverse (13211214612), we get a palindrome (34852425843).

The spelling of 21641211231 in words is "twenty-one billion, six hundred forty-one million, two hundred eleven thousand, two hundred thirty-one".