21170137 has 2 divisors, whose sum is σ = 21170138. Its totient is φ = 21170136.

The previous prime is 21170131. The next prime is 21170159. The reversal of 21170137 is 73107112.

It is an a-pointer prime, because the next prime (21170159) can be obtained adding 21170137 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20331081 + 839056 = 4509^2 + 916^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21170137 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21170131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585068 + 10585069.

It is an arithmetic number, because the mean of its divisors is an integer number (10585069).

Almost surely, 2^21170137 is an apocalyptic number.

It is an amenable number.

21170137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21170137 is an equidigital number, since it uses as much as digits as its factorization.

21170137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 21170137 is about 4601.1017158937. The cubic root of 21170137 is about 276.6354860749.

Adding to 21170137 its reverse (73107112), we get a palindrome (94277249).

The spelling of 21170137 in words is "twenty-one million, one hundred seventy thousand, one hundred thirty-seven".