21175471 has 2 divisors, whose sum is σ = 21175472. Its totient is φ = 21175470.

The previous prime is 21175463. The next prime is 21175477. The reversal of 21175471 is 17457112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21175471 - 2³ = 21175463 is a prime.

It is a super-3 number, since 3×21175471³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21175477) 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, 10587735 + 10587736.

It is an arithmetic number, because the mean of its divisors is an integer number (10587736).

Almost surely, 2^21175471 is an apocalyptic number.

21175471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21175471 is an equidigital number, since it uses as much as digits as its factorization.

21175471 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1960, while the sum is 28.

The square root of 21175471 is about 4601.6813231687. The cubic root of 21175471 is about 276.6587176955.

The spelling of 21175471 in words is "twenty-one million, one hundred seventy-five thousand, four hundred seventy-one".