71990087797 has 4 divisors (see below), whose sum is σ = 71992707660. Its totient is φ = 71987467936.

The previous prime is 71990087749. The next prime is 71990087881. The reversal of 71990087797 is 79778009917.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79778009917 = 7433 ⋅10732949.

It can be written as a sum of positive squares in 2 ways, for example, as 41481876241 + 30508211556 = 203671^2 + 174666^2 .

It is a cyclic number.

It is not a de Polignac number, because 71990087797 - 2⁷ = 71990087669 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 (71990084797) 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, 1268272 + ... + 1323817.

It is an arithmetic number, because the mean of its divisors is an integer number (17998176915).

Almost surely, 2^71990087797 is an apocalyptic number.

It is an amenable number.

71990087797 is a deficient number, since it is larger than the sum of its proper divisors (2619863).

71990087797 is a wasteful number, since it uses less digits than its factorization.

71990087797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2619862.

The product of its (nonzero) digits is 14002632, while the sum is 64.

The spelling of 71990087797 in words is "seventy-one billion, nine hundred ninety million, eighty-seven thousand, seven hundred ninety-seven".