71223121 has 2 divisors, whose sum is σ = 71223122. Its totient is φ = 71223120.

The previous prime is 71223083. The next prime is 71223127. The reversal of 71223121 is 12132217.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71216721 + 6400 = 8439^2 + 80^2 .

It is an emirp because it is prime and its reverse (12132217) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71223121 - 2¹⁹ = 70698833 is a prime.

It is not a weakly prime, because it can be changed into another prime (71223127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35611560 + 35611561.

It is an arithmetic number, because the mean of its divisors is an integer number (35611561).

Almost surely, 2^71223121 is an apocalyptic number.

It is an amenable number.

71223121 is a deficient number, since it is larger than the sum of its proper divisors (1).

71223121 is an equidigital number, since it uses as much as digits as its factorization.

71223121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 168, while the sum is 19.

The square root of 71223121 is about 8439.3791833286. The cubic root of 71223121 is about 414.5150788292.

Adding to 71223121 its reverse (12132217), we get a palindrome (83355338).

The spelling of 71223121 in words is "seventy-one million, two hundred twenty-three thousand, one hundred twenty-one".