81728027278 has 8 divisors (see below), whose sum is σ = 122603641272. Its totient is φ = 40860146856.

The previous prime is 81728027267. The next prime is 81728027291. The reversal of 81728027278 is 87272082718.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1906900 + ... + 1949287.

It is an arithmetic number, because the mean of its divisors is an integer number (15325455159).

Almost surely, 2^81728027278 is an apocalyptic number.

81728027278 is a deficient number, since it is larger than the sum of its proper divisors (40875613994).

81728027278 is a wasteful number, since it uses less digits than its factorization.

81728027278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3866786.

The product of its (nonzero) digits is 1404928, while the sum is 52.

The spelling of 81728027278 in words is "eighty-one billion, seven hundred twenty-eight million, twenty-seven thousand, two hundred seventy-eight".