71985511 has 16 divisors (see below), whose sum is σ = 81244800. Its totient is φ = 63318528.

The previous prime is 71985499. The next prime is 71985521. The reversal of 71985511 is 11558917.

It is not a de Polignac number, because 71985511 - 2⁷ = 71985383 is a prime.

It is a super-2 number, since 2×71985511² = 10363827587862242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71985521) 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 in 15 ways as a sum of consecutive naturals, for example, 28575 + ... + 30991.

It is an arithmetic number, because the mean of its divisors is an integer number (5077800).

Almost surely, 2^71985511 is an apocalyptic number.

71985511 is a deficient number, since it is larger than the sum of its proper divisors (9259289).

71985511 is a wasteful number, since it uses less digits than its factorization.

71985511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2538.

The product of its digits is 12600, while the sum is 37.

The square root of 71985511 is about 8484.4275587691. The cubic root of 71985511 is about 415.9888568730.

The spelling of 71985511 in words is "seventy-one million, nine hundred eighty-five thousand, five hundred eleven".