27791397397 has 2 divisors, whose sum is σ = 27791397398. Its totient is φ = 27791397396.

The previous prime is 27791397373. The next prime is 27791397407. The reversal of 27791397397 is 79379319772.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26828474436 + 962922961 = 163794^2 + 31031^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27791397397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27791397367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13895698698 + 13895698699.

It is an arithmetic number, because the mean of its divisors is an integer number (13895698699).

Almost surely, 2^27791397397 is an apocalyptic number.

It is an amenable number.

27791397397 is a deficient number, since it is larger than the sum of its proper divisors (1).

27791397397 is an equidigital number, since it uses as much as digits as its factorization.

27791397397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31505922, while the sum is 64.

The spelling of 27791397397 in words is "twenty-seven billion, seven hundred ninety-one million, three hundred ninety-seven thousand, three hundred ninety-seven".