21246637 has 2 divisors, whose sum is σ = 21246638. Its totient is φ = 21246636.

The previous prime is 21246629. The next prime is 21246683. The reversal of 21246637 is 73664212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15952036 + 5294601 = 3994^2 + 2301^2 .

It is a cyclic number.

It is not a de Polignac number, because 21246637 - 2³ = 21246629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21246599 and 21246608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10623318 + 10623319.

It is an arithmetic number, because the mean of its divisors is an integer number (10623319).

Almost surely, 2^21246637 is an apocalyptic number.

It is an amenable number.

21246637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21246637 is an equidigital number, since it uses as much as digits as its factorization.

21246637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 31.

The square root of 21246637 is about 4609.4074456485. The cubic root of 21246637 is about 276.9683004035.

The spelling of 21246637 in words is "twenty-one million, two hundred forty-six thousand, six hundred thirty-seven".