71821864567 has 4 divisors (see below), whose sum is σ = 71988505056. Its totient is φ = 71655224080.

The previous prime is 71821864559. The next prime is 71821864579. The reversal of 71821864567 is 76546812817.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76546812817 = 31727 ⋅2412671.

It is a cyclic number.

It is not a de Polignac number, because 71821864567 - 2³ = 71821864559 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 (71821864067) 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, 83319598 + ... + 83320459.

It is an arithmetic number, because the mean of its divisors is an integer number (17997126264).

Almost surely, 2^71821864567 is an apocalyptic number.

71821864567 is a deficient number, since it is larger than the sum of its proper divisors (166640489).

71821864567 is a wasteful number, since it uses less digits than its factorization.

71821864567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166640488.

The product of its digits is 4515840, while the sum is 55.

The spelling of 71821864567 in words is "seventy-one billion, eight hundred twenty-one million, eight hundred sixty-four thousand, five hundred sixty-seven".