21045039205831 has 2 divisors, whose sum is σ = 21045039205832. Its totient is φ = 21045039205830.

The previous prime is 21045039205703. The next prime is 21045039205873. The reversal of 21045039205831 is 13850293054012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21045039205831 - 2⁷ = 21045039205703 is a prime.

It is a super-2 number, since 2×21045039205831² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21045039205891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522519602915 + 10522519602916.

It is an arithmetic number, because the mean of its divisors is an integer number (10522519602916).

Almost surely, 2^{21045039205831} is an apocalyptic number.

21045039205831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045039205831 is an equidigital number, since it uses as much as digits as its factorization.

21045039205831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 21045039205831 in words is "twenty-one trillion, forty-five billion, thirty-nine million, two hundred five thousand, eight hundred thirty-one".