71186989 has 2 divisors, whose sum is σ = 71186990. Its totient is φ = 71186988.

The previous prime is 71186971. The next prime is 71187013. The reversal of 71186989 is 98968117.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45765225 + 25421764 = 6765^2 + 5042^2 .

It is an emirp because it is prime and its reverse (98968117) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71186989 - 2⁷ = 71186861 is a prime.

It is a super-2 number, since 2×71186989² = 10135174805772242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71186959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35593494 + 35593495.

It is an arithmetic number, because the mean of its divisors is an integer number (35593495).

Almost surely, 2^71186989 is an apocalyptic number.

It is an amenable number.

71186989 is a deficient number, since it is larger than the sum of its proper divisors (1).

71186989 is an equidigital number, since it uses as much as digits as its factorization.

71186989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 49.

The square root of 71186989 is about 8437.2382329765. The cubic root of 71186989 is about 414.4449714820. Note that the first 3 decimals are identical.

The spelling of 71186989 in words is "seventy-one million, one hundred eighty-six thousand, nine hundred eighty-nine".