27728778321 has 24 divisors (see below), whose sum is σ = 40843324704. Its totient is φ = 18123557760.

The previous prime is 27728778313. The next prime is 27728778401. The reversal of 27728778321 is 12387782772.

27728778321 is a `hidden beast` number, since 277 + 287 + 78 + 3 + 21 = 666.

It is not a de Polignac number, because 27728778321 - 2³ = 27728778313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (27728778821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18265 + ... + 236201.

It is an arithmetic number, because the mean of its divisors is an integer number (1701805196).

Almost surely, 2^27728778321 is an apocalyptic number.

It is an amenable number.

27728778321 is a deficient number, since it is larger than the sum of its proper divisors (13114546383).

27728778321 is a wasteful number, since it uses less digits than its factorization.

27728778321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218221 (or 218218 counting only the distinct ones).

The product of its digits is 3687936, while the sum is 54.

The spelling of 27728778321 in words is "twenty-seven billion, seven hundred twenty-eight million, seven hundred seventy-eight thousand, three hundred twenty-one".