71505139 has 2 divisors, whose sum is σ = 71505140. Its totient is φ = 71505138.

The previous prime is 71505121. The next prime is 71505143. The reversal of 71505139 is 93150517.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 71505139 - 2⁷ = 71505011 is a prime.

It is a super-2 number, since 2×71505139² = 10225969806818642, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 71505139.

It is not a weakly prime, because it can be changed into another prime (71505169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35752569 + 35752570.

It is an arithmetic number, because the mean of its divisors is an integer number (35752570).

Almost surely, 2^71505139 is an apocalyptic number.

71505139 is a deficient number, since it is larger than the sum of its proper divisors (1).

71505139 is an equidigital number, since it uses as much as digits as its factorization.

71505139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4725, while the sum is 31.

The square root of 71505139 is about 8456.0711326242. The cubic root of 71505139 is about 415.0614686131.

The spelling of 71505139 in words is "seventy-one million, five hundred five thousand, one hundred thirty-nine".