21171361 has 2 divisors, whose sum is σ = 21171362. Its totient is φ = 21171360.

The previous prime is 21171349. The next prime is 21171373. The reversal of 21171361 is 16317112.

It is a balanced prime because it is at equal distance from previous prime (21171349) and next prime (21171373).

It can be written as a sum of positive squares in only one way, i.e., 19633761 + 1537600 = 4431^2 + 1240^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21171361 is a prime.

It is equal to p_1340095 and since 21171361 and 1340095 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21171461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585680 + 10585681.

It is an arithmetic number, because the mean of its divisors is an integer number (10585681).

Almost surely, 2^21171361 is an apocalyptic number.

It is an amenable number.

21171361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21171361 is an equidigital number, since it uses as much as digits as its factorization.

21171361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252, while the sum is 22.

The square root of 21171361 is about 4601.2347255927. The cubic root of 21171361 is about 276.6408174104.

Adding to 21171361 its reverse (16317112), we get a palindrome (37488473).

The spelling of 21171361 in words is "twenty-one million, one hundred seventy-one thousand, three hundred sixty-one".