81192777349 has 8 divisors (see below), whose sum is σ = 85469278880. Its totient is φ = 76916595600.

The previous prime is 81192777317. The next prime is 81192777353. The reversal of 81192777349 is 94377729118.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81192777349 - 2⁵ = 81192777317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81192777293 and 81192777302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81192777389) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 581719 + ... + 707659.

It is an arithmetic number, because the mean of its divisors is an integer number (10683659860).

Almost surely, 2^81192777349 is an apocalyptic number.

It is an amenable number.

81192777349 is a deficient number, since it is larger than the sum of its proper divisors (4276501531).

81192777349 is a wasteful number, since it uses less digits than its factorization.

81192777349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159891.

The product of its digits is 5334336, while the sum is 58.

The spelling of 81192777349 in words is "eighty-one billion, one hundred ninety-two million, seven hundred seventy-seven thousand, three hundred forty-nine".