21331400231 has 4 divisors (see below), whose sum is σ = 21331709232. Its totient is φ = 21331091232.

The previous prime is 21331400227. The next prime is 21331400243. The reversal of 21331400231 is 13200413312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21331400231 - 2² = 21331400227 is a prime.

It is a super-2 number, since 2×21331400231² (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 (21331400291) 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, 1670 + ... + 206556.

It is an arithmetic number, because the mean of its divisors is an integer number (5332927308).

Almost surely, 2^21331400231 is an apocalyptic number.

21331400231 is a deficient number, since it is larger than the sum of its proper divisors (309001).

21331400231 is a wasteful number, since it uses less digits than its factorization.

21331400231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309000.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21331400231 its reverse (13200413312), we get a palindrome (34531813543).

The spelling of 21331400231 in words is "twenty-one billion, three hundred thirty-one million, four hundred thousand, two hundred thirty-one".