20521271 has 2 divisors, whose sum is σ = 20521272. Its totient is φ = 20521270.

The previous prime is 20521253. The next prime is 20521283. The reversal of 20521271 is 17212502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20521271 - 2²² = 16326967 is a prime.

It is a super-2 number, since 2×20521271² = 842245126910882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20521871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10260635 + 10260636.

It is an arithmetic number, because the mean of its divisors is an integer number (10260636).

Almost surely, 2^20521271 is an apocalyptic number.

20521271 is a deficient number, since it is larger than the sum of its proper divisors (1).

20521271 is an equidigital number, since it uses as much as digits as its factorization.

20521271 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 20521271 is about 4530.0409490423. The cubic root of 20521271 is about 273.7798104912.

Adding to 20521271 its reverse (17212502), we get a palindrome (37733773).

The spelling of 20521271 in words is "twenty million, five hundred twenty-one thousand, two hundred seventy-one".