71121989 has 2 divisors, whose sum is σ = 71121990. Its totient is φ = 71121988.

The previous prime is 71121983. The next prime is 71122001. The reversal of 71121989 is 98912117.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69722500 + 1399489 = 8350^2 + 1183^2 .

It is an emirp because it is prime and its reverse (98912117) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71121989 is a prime.

It is a super-2 number, since 2×71121989² = 10116674638632242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71121983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35560994 + 35560995.

It is an arithmetic number, because the mean of its divisors is an integer number (35560995).

Almost surely, 2^71121989 is an apocalyptic number.

It is an amenable number.

71121989 is a deficient number, since it is larger than the sum of its proper divisors (1).

71121989 is an equidigital number, since it uses as much as digits as its factorization.

71121989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 38.

The square root of 71121989 is about 8433.3853819211. The cubic root of 71121989 is about 414.3187914647.

The spelling of 71121989 in words is "seventy-one million, one hundred twenty-one thousand, nine hundred eighty-nine".