71006581 has 4 divisors (see below), whose sum is σ = 71276832. Its totient is φ = 70736332.

The previous prime is 71006561. The next prime is 71006597. The reversal of 71006581 is 18560017.

It is a happy number.

71006581 is nontrivially palindromic in base 14.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 71006581 - 2¹¹ = 71004533 is a prime.

It is a super-2 number, since 2×71006581² = 10083869090619122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71006521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134731 + ... + 135256.

It is an arithmetic number, because the mean of its divisors is an integer number (17819208).

Almost surely, 2^71006581 is an apocalyptic number.

It is an amenable number.

71006581 is a deficient number, since it is larger than the sum of its proper divisors (270251).

71006581 is a wasteful number, since it uses less digits than its factorization.

71006581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270250.

The product of its (nonzero) digits is 1680, while the sum is 28.

The square root of 71006581 is about 8426.5402746323. The cubic root of 71006581 is about 414.0945683130.

Adding to 71006581 its reverse (18560017), we get a palindrome (89566598).

Subtracting from 71006581 its reverse (18560017), we obtain a square (52446564 = 7242²).

The spelling of 71006581 in words is "seventy-one million, six thousand, five hundred eighty-one".