27942719921 has 2 divisors, whose sum is σ = 27942719922. Its totient is φ = 27942719920.

The previous prime is 27942719899. The next prime is 27942719977. The reversal of 27942719921 is 12991724972.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26070946225 + 1871773696 = 161465^2 + 43264^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27942719921 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (27942719221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13971359960 + 13971359961.

It is an arithmetic number, because the mean of its divisors is an integer number (13971359961).

Almost surely, 2^27942719921 is an apocalyptic number.

It is an amenable number.

27942719921 is a deficient number, since it is larger than the sum of its proper divisors (1).

27942719921 is an equidigital number, since it uses as much as digits as its factorization.

27942719921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1143072, while the sum is 53.

The spelling of 27942719921 in words is "twenty-seven billion, nine hundred forty-two million, seven hundred nineteen thousand, nine hundred twenty-one".