21331031100031 has 4 divisors (see below), whose sum is σ = 21333065155632. Its totient is φ = 21328997044432.

The previous prime is 21331031100013. The next prime is 21331031100091. The reversal of 21331031100031 is 13000113013312.

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 21331031100031 - 2¹⁷ = 21331030968959 is a prime.

It is a super-2 number, since 2×21331031100031² (a number of 27 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 = 21331031099981 and 21331031100008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331031100091) 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, 1017012070 + ... + 1017033043.

It is an arithmetic number, because the mean of its divisors is an integer number (5333266288908).

Almost surely, 2^{21331031100031} is an apocalyptic number.

21331031100031 is a deficient number, since it is larger than the sum of its proper divisors (2034055601).

21331031100031 is a wasteful number, since it uses less digits than its factorization.

21331031100031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2034055600.

The product of its (nonzero) digits is 162, while the sum is 19.

Adding to 21331031100031 its reverse (13000113013312), we get a palindrome (34331144113343).

The spelling of 21331031100031 in words is "twenty-one trillion, three hundred thirty-one billion, thirty-one million, one hundred thousand, thirty-one".