71251021 has 2 divisors, whose sum is σ = 71251022. Its totient is φ = 71251020.

The previous prime is 71250973. The next prime is 71251039. The reversal of 71251021 is 12015217.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70795396 + 455625 = 8414^2 + 675^2 .

It is an emirp because it is prime and its reverse (12015217) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71251021 - 2²¹ = 69153869 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71251021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71251091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35625510 + 35625511.

It is an arithmetic number, because the mean of its divisors is an integer number (35625511).

Almost surely, 2^71251021 is an apocalyptic number.

It is an amenable number.

71251021 is a deficient number, since it is larger than the sum of its proper divisors (1).

71251021 is an equidigital number, since it uses as much as digits as its factorization.

71251021 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 71251021 is about 8441.0319866708. The cubic root of 71251021 is about 414.5691973082.

Adding to 71251021 its reverse (12015217), we get a palindrome (83266238).

The spelling of 71251021 in words is "seventy-one million, two hundred fifty-one thousand, twenty-one".