21735137 has 2 divisors, whose sum is σ = 21735138. Its totient is φ = 21735136.

The previous prime is 21735089. The next prime is 21735139. The reversal of 21735137 is 73153712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19351201 + 2383936 = 4399^2 + 1544^2 .

It is a cyclic number.

It is not a de Polignac number, because 21735137 - 2⁶ = 21735073 is a prime.

Together with 21735139, 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 (21735139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10867568 + 10867569.

It is an arithmetic number, because the mean of its divisors is an integer number (10867569).

Almost surely, 2^21735137 is an apocalyptic number.

It is an amenable number.

21735137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21735137 is an equidigital number, since it uses as much as digits as its factorization.

21735137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4410, while the sum is 29.

The square root of 21735137 is about 4662.0957733620. The cubic root of 21735137 is about 279.0749104058.

Adding to 21735137 its reverse (73153712), we get a palindrome (94888849).

The spelling of 21735137 in words is "twenty-one million, seven hundred thirty-five thousand, one hundred thirty-seven".