21144577 has 2 divisors, whose sum is σ = 21144578. Its totient is φ = 21144576.

The previous prime is 21144559. The next prime is 21144589. The reversal of 21144577 is 77544112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17606416 + 3538161 = 4196^2 + 1881^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144577 - 2¹¹ = 21142529 is a prime.

It is not a weakly prime, because it can be changed into another prime (21144547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572288 + 10572289.

It is an arithmetic number, because the mean of its divisors is an integer number (10572289).

Almost surely, 2^21144577 is an apocalyptic number.

It is an amenable number.

21144577 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144577 is an equidigital number, since it uses as much as digits as its factorization.

21144577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7840, while the sum is 31.

The square root of 21144577 is about 4598.3232813712. The cubic root of 21144577 is about 276.5241082631.

Adding to 21144577 its reverse (77544112), we get a palindrome (98688689).

The spelling of 21144577 in words is "twenty-one million, one hundred forty-four thousand, five hundred seventy-seven".