71388661 has 8 divisors (see below), whose sum is σ = 75714264. Its totient is φ = 67077120.

The previous prime is 71388631. The next prime is 71388673. The reversal of 71388661 is 16688317.

It can be written as a sum of positive squares in 4 ways, for example, as 28026436 + 43362225 = 5294^2 + 6585^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71388661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71388631) 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 7 ways as a sum of consecutive naturals, for example, 8061 + ... + 14413.

It is an arithmetic number, because the mean of its divisors is an integer number (9464283).

Almost surely, 2^71388661 is an apocalyptic number.

It is an amenable number.

71388661 is a deficient number, since it is larger than the sum of its proper divisors (4325603).

71388661 is a wasteful number, since it uses less digits than its factorization.

71388661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7031.

The product of its digits is 48384, while the sum is 40.

The square root of 71388661 is about 8449.1810845786. The cubic root of 71388661 is about 414.8359752432.

The spelling of 71388661 in words is "seventy-one million, three hundred eighty-eight thousand, six hundred sixty-one".