71638042581 has 96 divisors (see below), whose sum is σ = 124263526400. Its totient is φ = 39724038144.

The previous prime is 71638042559. The next prime is 71638042589. The reversal of 71638042581 is 18524083617.

71638042581 is a `hidden beast` number, since 7 + 1 + 63 + 8 + 0 + 4 + 2 + 581 = 666.

It is not a de Polignac number, because 71638042581 - 2¹⁵ = 71638009813 is a prime.

It is a super-2 number, since 2×71638042581² (a number of 23 digits) 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 (71638042589) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 65903820 + ... + 65904906.

Almost surely, 2^71638042581 is an apocalyptic number.

It is an amenable number.

71638042581 is a deficient number, since it is larger than the sum of its proper divisors (52625483819).

71638042581 is a wasteful number, since it uses less digits than its factorization.

71638042581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1728 (or 1711 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 71638042581 in words is "seventy-one billion, six hundred thirty-eight million, forty-two thousand, five hundred eighty-one".