71372611661 has 8 divisors (see below), whose sum is σ = 76886059320. Its totient is φ = 65862484992.

The previous prime is 71372611649. The next prime is 71372611721. The reversal of 71372611661 is 16611627317.

It can be written as a sum of positive squares in 4 ways, for example, as 32218096036 + 39154515625 = 179494^2 + 197875^2 .

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-71372611661 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 (71372611561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 785516 + ... + 871653.

It is an arithmetic number, because the mean of its divisors is an integer number (9610757415).

Almost surely, 2^71372611661 is an apocalyptic number.

It is an amenable number.

71372611661 is a deficient number, since it is larger than the sum of its proper divisors (5513447659).

71372611661 is a wasteful number, since it uses less digits than its factorization.

71372611661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1660495.

The product of its digits is 63504, while the sum is 41.

The spelling of 71372611661 in words is "seventy-one billion, three hundred seventy-two million, six hundred eleven thousand, six hundred sixty-one".