71239009 has 2 divisors, whose sum is σ = 71239010. Its totient is φ = 71239008.

The previous prime is 71238997. The next prime is 71239039. The reversal of 71239009 is 90093217.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53363025 + 17875984 = 7305^2 + 4228^2 .

It is a cyclic number.

It is not a de Polignac number, because 71239009 - 2⁵ = 71238977 is a prime.

It is equal to p_4186615 and since 71239009 and 4186615 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (71239039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35619504 + 35619505.

It is an arithmetic number, because the mean of its divisors is an integer number (35619505).

Almost surely, 2^71239009 is an apocalyptic number.

It is an amenable number.

71239009 is a deficient number, since it is larger than the sum of its proper divisors (1).

71239009 is an equidigital number, since it uses as much as digits as its factorization.

71239009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 31.

The square root of 71239009 is about 8440.3204323059. The cubic root of 71239009 is about 414.5458989985.

The spelling of 71239009 in words is "seventy-one million, two hundred thirty-nine thousand, nine".