21022471 has 2 divisors, whose sum is σ = 21022472. Its totient is φ = 21022470.

The previous prime is 21022459. The next prime is 21022517. The reversal of 21022471 is 17422012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022471 is a prime.

It is a super-3 number, since 3×21022471³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21022411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511235 + 10511236.

It is an arithmetic number, because the mean of its divisors is an integer number (10511236).

Almost surely, 2^21022471 is an apocalyptic number.

21022471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022471 is an equidigital number, since it uses as much as digits as its factorization.

21022471 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21022471 is about 4585.0268265300. The cubic root of 21022471 is about 275.9907885675.

Adding to 21022471 its reverse (17422012), we get a palindrome (38444483).

The spelling of 21022471 in words is "twenty-one million, twenty-two thousand, four hundred seventy-one".