21727477 has 2 divisors, whose sum is σ = 21727478. Its totient is φ = 21727476.

The previous prime is 21727463. The next prime is 21727487. The reversal of 21727477 is 77472712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12327121 + 9400356 = 3511^2 + 3066^2 .

It is a cyclic number.

It is not a de Polignac number, because 21727477 - 2¹⁵ = 21694709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21727487) 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, 10863738 + 10863739.

It is an arithmetic number, because the mean of its divisors is an integer number (10863739).

Almost surely, 2^21727477 is an apocalyptic number.

It is an amenable number.

21727477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21727477 is an equidigital number, since it uses as much as digits as its factorization.

21727477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38416, while the sum is 37.

The square root of 21727477 is about 4661.2741820236. The cubic root of 21727477 is about 279.0421222528.

The spelling of 21727477 in words is "twenty-one million, seven hundred twenty-seven thousand, four hundred seventy-seven".