81976320501 has 4 divisors (see below), whose sum is σ = 109301760672. Its totient is φ = 54650880332.

The previous prime is 81976320463. The next prime is 81976320539. The reversal of 81976320501 is 10502367918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (81976320463) and next prime (81976320539).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81976320501 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81976320541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13662720081 + ... + 13662720086.

It is an arithmetic number, because the mean of its divisors is an integer number (27325440168).

Almost surely, 2^81976320501 is an apocalyptic number.

It is an amenable number.

81976320501 is a deficient number, since it is larger than the sum of its proper divisors (27325440171).

81976320501 is a wasteful number, since it uses less digits than its factorization.

81976320501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27325440170.

The product of its (nonzero) digits is 90720, while the sum is 42.

The spelling of 81976320501 in words is "eighty-one billion, nine hundred seventy-six million, three hundred twenty thousand, five hundred one".