21234531161 has 2 divisors, whose sum is σ = 21234531162. Its totient is φ = 21234531160.

The previous prime is 21234531151. The next prime is 21234531163. The reversal of 21234531161 is 16113543212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12746410000 + 8488121161 = 112900^2 + 92131^2 .

It is a cyclic number.

It is not a de Polignac number, because 21234531161 - 2²² = 21230336857 is a prime.

Together with 21234531163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21234531163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617265580 + 10617265581.

It is an arithmetic number, because the mean of its divisors is an integer number (10617265581).

Almost surely, 2^21234531161 is an apocalyptic number.

It is an amenable number.

21234531161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234531161 is an equidigital number, since it uses as much as digits as its factorization.

21234531161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 29.

The spelling of 21234531161 in words is "twenty-one billion, two hundred thirty-four million, five hundred thirty-one thousand, one hundred sixty-one".