71128981 has 16 divisors (see below), whose sum is σ = 89071488. Its totient is φ = 55180800.

The previous prime is 71128963. The next prime is 71128987. The reversal of 71128981 is 18982117.

It is a cyclic number.

It is not a de Polignac number, because 71128981 - 2⁹ = 71128469 is a prime.

It is a super-2 number, since 2×71128981² = 10118663876196722, 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 71128981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71128987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16641 + ... + 20473.

It is an arithmetic number, because the mean of its divisors is an integer number (5566968).

Almost surely, 2^71128981 is an apocalyptic number.

It is an amenable number.

71128981 is a deficient number, since it is larger than the sum of its proper divisors (17942507).

71128981 is a wasteful number, since it uses less digits than its factorization.

71128981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4092.

The product of its digits is 8064, while the sum is 37.

The square root of 71128981 is about 8433.7999146292. The cubic root of 71128981 is about 414.3323682412.

It can be divided in two parts, 711 and 28981, that added together give a palindrome (29692).

The spelling of 71128981 in words is "seventy-one million, one hundred twenty-eight thousand, nine hundred eighty-one".