71971409 has 2 divisors, whose sum is σ = 71971410. Its totient is φ = 71971408.

The previous prime is 71971391. The next prime is 71971423. The reversal of 71971409 is 90417917.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71910400 + 61009 = 8480^2 + 247^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71971409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71971499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35985704 + 35985705.

It is an arithmetic number, because the mean of its divisors is an integer number (35985705).

Almost surely, 2^71971409 is an apocalyptic number.

It is an amenable number.

71971409 is a deficient number, since it is larger than the sum of its proper divisors (1).

71971409 is an equidigital number, since it uses as much as digits as its factorization.

71971409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15876, while the sum is 38.

The square root of 71971409 is about 8483.5964661221. The cubic root of 71971409 is about 415.9616909527.

The spelling of 71971409 in words is "seventy-one million, nine hundred seventy-one thousand, four hundred nine".