71808381 has 6 divisors (see below), whose sum is σ = 103723230. Its totient is φ = 47872248.

The previous prime is 71808377. The next prime is 71808397. The reversal of 71808381 is 18380817.

It can be written as a sum of positive squares in only one way, i.e., 69056100 + 2752281 = 8310^2 + 1659^2 .

It is not a de Polignac number, because 71808381 - 2² = 71808377 is a prime.

It is a super-2 number, since 2×71808381² = 10312887163682322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71808371) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3989346 + ... + 3989363.

It is an arithmetic number, because the mean of its divisors is an integer number (17287205).

Almost surely, 2^71808381 is an apocalyptic number.

It is an amenable number.

71808381 is a deficient number, since it is larger than the sum of its proper divisors (31914849).

71808381 is a wasteful number, since it uses less digits than its factorization.

71808381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7978715 (or 7978712 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 71808381 is about 8473.9825937985. The cubic root of 71808381 is about 415.6473778518.

The spelling of 71808381 in words is "seventy-one million, eight hundred eight thousand, three hundred eighty-one".