81765017493 has 4 divisors (see below), whose sum is σ = 109020023328. Its totient is φ = 54510011660.

The previous prime is 81765017491. The next prime is 81765017497. The reversal of 81765017493 is 39471056718.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 81765017493 - 2¹ = 81765017491 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81765017491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13627502913 + ... + 13627502918.

It is an arithmetic number, because the mean of its divisors is an integer number (27255005832).

Almost surely, 2^81765017493 is an apocalyptic number.

It is an amenable number.

81765017493 is a deficient number, since it is larger than the sum of its proper divisors (27255005835).

81765017493 is a wasteful number, since it uses less digits than its factorization.

81765017493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27255005834.

The product of its (nonzero) digits is 1270080, while the sum is 51.

The spelling of 81765017493 in words is "eighty-one billion, seven hundred sixty-five million, seventeen thousand, four hundred ninety-three".