21399509200831 has 2 divisors, whose sum is σ = 21399509200832. Its totient is φ = 21399509200830.

The previous prime is 21399509200793. The next prime is 21399509200963. The reversal of 21399509200831 is 13800290599312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21399509200831 - 2⁷ = 21399509200703 is a prime.

It is a super-2 number, since 2×21399509200831² (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 (21399509200631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10699754600415 + 10699754600416.

It is an arithmetic number, because the mean of its divisors is an integer number (10699754600416).

Almost surely, 2^{21399509200831} is an apocalyptic number.

21399509200831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21399509200831 is an equidigital number, since it uses as much as digits as its factorization.

21399509200831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1049760, while the sum is 52.

The spelling of 21399509200831 in words is "twenty-one trillion, three hundred ninety-nine billion, five hundred nine million, two hundred thousand, eight hundred thirty-one".