71215421 has 2 divisors, whose sum is σ = 71215422. Its totient is φ = 71215420.

The previous prime is 71215409. The next prime is 71215447. The reversal of 71215421 is 12451217.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42432196 + 28783225 = 6514^2 + 5365^2 .

It is an emirp because it is prime and its reverse (12451217) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71215421 - 2¹⁰ = 71214397 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71215321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35607710 + 35607711.

It is an arithmetic number, because the mean of its divisors is an integer number (35607711).

Almost surely, 2^71215421 is an apocalyptic number.

It is an amenable number.

71215421 is a deficient number, since it is larger than the sum of its proper divisors (1).

71215421 is an equidigital number, since it uses as much as digits as its factorization.

71215421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 560, while the sum is 23.

The square root of 71215421 is about 8438.9229763045. The cubic root of 71215421 is about 414.5001404165.

Adding to 71215421 its reverse (12451217), we get a palindrome (83666638).

The spelling of 71215421 in words is "seventy-one million, two hundred fifteen thousand, four hundred twenty-one".