71821256705 has 24 divisors (see below), whose sum is σ = 98851669056. Its totient is φ = 49962603680.

The previous prime is 71821256687. The next prime is 71821256707. The reversal of 71821256705 is 50765212817.

It is not a de Polignac number, because 71821256705 - 2¹⁸ = 71820994561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71821256707) 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 23 ways as a sum of consecutive naturals, for example, 2566799 + ... + 2594628.

It is an arithmetic number, because the mean of its divisors is an integer number (4118819544).

Almost surely, 2^71821256705 is an apocalyptic number.

It is an amenable number.

71821256705 is a deficient number, since it is larger than the sum of its proper divisors (27030412351).

71821256705 is a wasteful number, since it uses less digits than its factorization.

71821256705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5161477 (or 5161466 counting only the distinct ones).

The product of its (nonzero) digits is 235200, while the sum is 44.

The spelling of 71821256705 in words is "seventy-one billion, eight hundred twenty-one million, two hundred fifty-six thousand, seven hundred five".