21030637 has 2 divisors, whose sum is σ = 21030638. Its totient is φ = 21030636.

The previous prime is 21030619. The next prime is 21030677. The reversal of 21030637 is 73603012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19527561 + 1503076 = 4419^2 + 1226^2 .

It is a cyclic number.

It is not a de Polignac number, because 21030637 - 2¹⁹ = 20506349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21030677) 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, 10515318 + 10515319.

It is an arithmetic number, because the mean of its divisors is an integer number (10515319).

Almost surely, 2^21030637 is an apocalyptic number.

It is an amenable number.

21030637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030637 is an equidigital number, since it uses as much as digits as its factorization.

21030637 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 22.

The square root of 21030637 is about 4585.9172473999. The cubic root of 21030637 is about 276.0265193660.

Adding to 21030637 its reverse (73603012), we get a palindrome (94633649).

The spelling of 21030637 in words is "twenty-one million, thirty thousand, six hundred thirty-seven".