21050137 has 2 divisors, whose sum is σ = 21050138. Its totient is φ = 21050136.

The previous prime is 21050111. The next prime is 21050149. The reversal of 21050137 is 73105012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13808656 + 7241481 = 3716^2 + 2691^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050137 - 2¹⁹ = 20525849 is a prime.

It is not a weakly prime, because it can be changed into another prime (21050737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525068 + 10525069.

It is an arithmetic number, because the mean of its divisors is an integer number (10525069).

Almost surely, 2^21050137 is an apocalyptic number.

It is an amenable number.

21050137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050137 is an equidigital number, since it uses as much as digits as its factorization.

21050137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 210, while the sum is 19.

The square root of 21050137 is about 4588.0428289195. The cubic root of 21050137 is about 276.1118053291. Note that the first 3 decimals are identical.

Adding to 21050137 its reverse (73105012), we get a palindrome (94155149).

The spelling of 21050137 in words is "twenty-one million, fifty thousand, one hundred thirty-seven".