71581969 has 2 divisors, whose sum is σ = 71581970. Its totient is φ = 71581968.

The previous prime is 71581967. The next prime is 71581981. The reversal of 71581969 is 96918517.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41770369 + 29811600 = 6463^2 + 5460^2 .

It is a cyclic number.

It is not a de Polignac number, because 71581969 - 2¹ = 71581967 is a prime.

It is a super-2 number, since 2×71581969² = 10247956571833922, which contains 22 as substring.

Together with 71581967, it forms a pair of twin primes.

It is a nialpdrome in base 16.

It is a zygodrome in base 16.

It is not a weakly prime, because it can be changed into another prime (71581967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35790984 + 35790985.

It is an arithmetic number, because the mean of its divisors is an integer number (35790985).

Almost surely, 2^71581969 is an apocalyptic number.

It is an amenable number.

71581969 is a deficient number, since it is larger than the sum of its proper divisors (1).

71581969 is an equidigital number, since it uses as much as digits as its factorization.

71581969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 46.

The square root of 71581969 is about 8460.6128028648. The cubic root of 71581969 is about 415.2100721894.

The spelling of 71581969 in words is "seventy-one million, five hundred eighty-one thousand, nine hundred sixty-nine".