21159161 has 2 divisors, whose sum is σ = 21159162. Its totient is φ = 21159160.

The previous prime is 21159133. The next prime is 21159163. The reversal of 21159161 is 16195112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 511225 = 4544^2 + 715^2 .

It is a cyclic number.

It is not a de Polignac number, because 21159161 - 2¹⁴ = 21142777 is a prime.

Together with 21159163, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21159161.

It is not a weakly prime, because it can be changed into another prime (21159163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579580 + 10579581.

It is an arithmetic number, because the mean of its divisors is an integer number (10579581).

Almost surely, 2^21159161 is an apocalyptic number.

It is an amenable number.

21159161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21159161 is an equidigital number, since it uses as much as digits as its factorization.

21159161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 26.

The square root of 21159161 is about 4599.9088034438. The cubic root of 21159161 is about 276.5876690958.

The spelling of 21159161 in words is "twenty-one million, one hundred fifty-nine thousand, one hundred sixty-one".