21121442231 has 4 divisors (see below), whose sum is σ = 21238135464. Its totient is φ = 21004749000.

The previous prime is 21121442183. The next prime is 21121442239. The reversal of 21121442231 is 13224412112.

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 21121442231 - 2¹⁰ = 21121441207 is a prime.

It is a super-2 number, since 2×21121442231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121442197 and 21121442206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121442239) 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, 58346345 + ... + 58346706.

It is an arithmetic number, because the mean of its divisors is an integer number (5309533866).

Almost surely, 2^21121442231 is an apocalyptic number.

21121442231 is a deficient number, since it is larger than the sum of its proper divisors (116693233).

21121442231 is a wasteful number, since it uses less digits than its factorization.

21121442231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116693232.

The product of its digits is 768, while the sum is 23.

Adding to 21121442231 its reverse (13224412112), we get a palindrome (34345854343).

The spelling of 21121442231 in words is "twenty-one billion, one hundred twenty-one million, four hundred forty-two thousand, two hundred thirty-one".