81776959538 has 16 divisors (see below), whose sum is σ = 130572324000. Its totient is φ = 38301211872.

The previous prime is 81776959513. The next prime is 81776959577. The reversal of 81776959538 is 83595967718.

It is a super-2 number, since 2×81776959538² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

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, 12086648 + ... + 12093411.

It is an arithmetic number, because the mean of its divisors is an integer number (8160770250).

Almost surely, 2^81776959538 is an apocalyptic number.

81776959538 is a deficient number, since it is larger than the sum of its proper divisors (48795364462).

81776959538 is a wasteful number, since it uses less digits than its factorization.

81776959538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24180169.

The product of its digits is 114307200, while the sum is 68.

The spelling of 81776959538 in words is "eighty-one billion, seven hundred seventy-six million, nine hundred fifty-nine thousand, five hundred thirty-eight".