71051221 has 2 divisors, whose sum is σ = 71051222. Its totient is φ = 71051220.

The previous prime is 71051219. The next prime is 71051261. The reversal of 71051221 is 12215017.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69906321 + 1144900 = 8361^2 + 1070^2 .

It is a cyclic number.

It is not a de Polignac number, because 71051221 - 2¹ = 71051219 is a prime.

Together with 71051219, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71051261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35525610 + 35525611.

It is an arithmetic number, because the mean of its divisors is an integer number (35525611).

Almost surely, 2^71051221 is an apocalyptic number.

It is an amenable number.

71051221 is a deficient number, since it is larger than the sum of its proper divisors (1).

71051221 is an equidigital number, since it uses as much as digits as its factorization.

71051221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 71051221 is about 8429.1886323655. The cubic root of 71051221 is about 414.1813269810.

Adding to 71051221 its reverse (12215017), we get a palindrome (83266238).

The spelling of 71051221 in words is "seventy-one million, fifty-one thousand, two hundred twenty-one".