21350805239161 has 2 divisors, whose sum is σ = 21350805239162. Its totient is φ = 21350805239160.

The previous prime is 21350805239131. The next prime is 21350805239219. The reversal of 21350805239161 is 16193250805312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15407234292025 + 5943570947136 = 3925205^2 + 2437944^2 .

It is a cyclic number.

It is not a de Polignac number, because 21350805239161 - 2⁵ = 21350805239129 is a prime.

It is not a weakly prime, because it can be changed into another prime (21350805239131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675402619580 + 10675402619581.

It is an arithmetic number, because the mean of its divisors is an integer number (10675402619581).

Almost surely, 2^{21350805239161} is an apocalyptic number.

It is an amenable number.

21350805239161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21350805239161 is an equidigital number, since it uses as much as digits as its factorization.

21350805239161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 388800, while the sum is 46.

The spelling of 21350805239161 in words is "twenty-one trillion, three hundred fifty billion, eight hundred five million, two hundred thirty-nine thousand, one hundred sixty-one".