21064471 has 2 divisors, whose sum is σ = 21064472. Its totient is φ = 21064470.

The previous prime is 21064363. The next prime is 21064499. The reversal of 21064471 is 17446012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21064471 - 2¹⁷ = 20933399 is a prime.

It is a super-3 number, since 3×21064471³ (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 (21064271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532235 + 10532236.

It is an arithmetic number, because the mean of its divisors is an integer number (10532236).

Almost surely, 2^21064471 is an apocalyptic number.

21064471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064471 is an equidigital number, since it uses as much as digits as its factorization.

21064471 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21064471 is about 4589.6046670710. The cubic root of 21064471 is about 276.1744634900.

The spelling of 21064471 in words is "twenty-one million, sixty-four thousand, four hundred seventy-one".