27720783521 has 2 divisors, whose sum is σ = 27720783522. Its totient is φ = 27720783520.

The previous prime is 27720783509. The next prime is 27720783569. The reversal of 27720783521 is 12538702772.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27526459921 + 194323600 = 165911^2 + 13940^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27720783521 is a prime.

It is not a weakly prime, because it can be changed into another prime (27720783421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13860391760 + 13860391761.

It is an arithmetic number, because the mean of its divisors is an integer number (13860391761).

Almost surely, 2^27720783521 is an apocalyptic number.

It is an amenable number.

27720783521 is a deficient number, since it is larger than the sum of its proper divisors (1).

27720783521 is an equidigital number, since it uses as much as digits as its factorization.

27720783521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 329280, while the sum is 44.

The spelling of 27720783521 in words is "twenty-seven billion, seven hundred twenty million, seven hundred eighty-three thousand, five hundred twenty-one".