81650671457 has 4 divisors (see below), whose sum is σ = 81739519680. Its totient is φ = 81561823236.

The previous prime is 81650671451. The next prime is 81650671481. The reversal of 81650671457 is 75417605618.

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 a de Polignac number, because none of the positive numbers 2^k-81650671457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81650671451) 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, 44422733 + ... + 44424570.

It is an arithmetic number, because the mean of its divisors is an integer number (20434879920).

Almost surely, 2^81650671457 is an apocalyptic number.

It is an amenable number.

81650671457 is a deficient number, since it is larger than the sum of its proper divisors (88848223).

81650671457 is an equidigital number, since it uses as much as digits as its factorization.

81650671457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88848222.

The product of its (nonzero) digits is 1411200, while the sum is 50.

The spelling of 81650671457 in words is "eighty-one billion, six hundred fifty million, six hundred seventy-one thousand, four hundred fifty-seven".