21652171 has 2 divisors, whose sum is σ = 21652172. Its totient is φ = 21652170.

The previous prime is 21652159. The next prime is 21652181. The reversal of 21652171 is 17125612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21652171 - 2²³ = 13263563 is a prime.

It is a super-3 number, since 3×21652171³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21652121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10826085 + 10826086.

It is an arithmetic number, because the mean of its divisors is an integer number (10826086).

Almost surely, 2^21652171 is an apocalyptic number.

21652171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21652171 is an equidigital number, since it uses as much as digits as its factorization.

21652171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 25.

The square root of 21652171 is about 4653.1893363585. The cubic root of 21652171 is about 278.7193685633.

Adding to 21652171 its reverse (17125612), we get a palindrome (38777783).

The spelling of 21652171 in words is "twenty-one million, six hundred fifty-two thousand, one hundred seventy-one".