21275477 has 2 divisors, whose sum is σ = 21275478. Its totient is φ = 21275476.

The previous prime is 21275467. The next prime is 21275489. The reversal of 21275477 is 77457212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21169201 + 106276 = 4601^2 + 326^2 .

It is a cyclic number.

It is not a de Polignac number, because 21275477 - 2⁴ = 21275461 is a prime.

It is a super-6 number, since 6×21275477⁶ (a number of 45 digits) contains 666666 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21275467) 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, 10637738 + 10637739.

It is an arithmetic number, because the mean of its divisors is an integer number (10637739).

Almost surely, 2^21275477 is an apocalyptic number.

It is an amenable number.

21275477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21275477 is an equidigital number, since it uses as much as digits as its factorization.

21275477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27440, while the sum is 35.

The square root of 21275477 is about 4612.5347695166. The cubic root of 21275477 is about 277.0935618639.

The spelling of 21275477 in words is "twenty-one million, two hundred seventy-five thousand, four hundred seventy-seven".