21257077 has 2 divisors, whose sum is σ = 21257078. Its totient is φ = 21257076.

The previous prime is 21257059. The next prime is 21257101. The reversal of 21257077 is 77075212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21150801 + 106276 = 4599^2 + 326^2 .

It is a cyclic number.

It is not a de Polignac number, because 21257077 - 2²³ = 12868469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21257017) 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, 10628538 + 10628539.

It is an arithmetic number, because the mean of its divisors is an integer number (10628539).

Almost surely, 2^21257077 is an apocalyptic number.

It is an amenable number.

21257077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21257077 is an equidigital number, since it uses as much as digits as its factorization.

21257077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6860, while the sum is 31.

The square root of 21257077 is about 4610.5397731719. The cubic root of 21257077 is about 277.0136577869.

The spelling of 21257077 in words is "twenty-one million, two hundred fifty-seven thousand, seventy-seven".