71881531 has 4 divisors (see below), whose sum is σ = 71919592. Its totient is φ = 71843472.

The previous prime is 71881507. The next prime is 71881549. The reversal of 71881531 is 13518817.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 71881531 - 2¹⁹ = 71357243 is a prime.

It is a super-2 number, since 2×71881531² = 10333908997807922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71881501) 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 3 ways as a sum of consecutive naturals, for example, 16041 + ... + 20026.

It is an arithmetic number, because the mean of its divisors is an integer number (17979898).

Almost surely, 2^71881531 is an apocalyptic number.

71881531 is a deficient number, since it is larger than the sum of its proper divisors (38061).

71881531 is a wasteful number, since it uses less digits than its factorization.

71881531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38060.

The product of its digits is 6720, while the sum is 34.

The square root of 71881531 is about 8478.2976475234. The cubic root of 71881531 is about 415.7884676377.

The spelling of 71881531 in words is "seventy-one million, eight hundred eighty-one thousand, five hundred thirty-one".