27172697681 has 2 divisors, whose sum is σ = 27172697682. Its totient is φ = 27172697680.

The previous prime is 27172697659. The next prime is 27172697687. The reversal of 27172697681 is 18679627172.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24156930625 + 3015767056 = 155425^2 + 54916^2 .

It is a cyclic number.

It is not a de Polignac number, because 27172697681 - 2¹⁴ = 27172681297 is a prime.

It is a super-2 number, since 2×27172697681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (27172697687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13586348840 + 13586348841.

It is an arithmetic number, because the mean of its divisors is an integer number (13586348841).

Almost surely, 2^27172697681 is an apocalyptic number.

It is an amenable number.

27172697681 is a deficient number, since it is larger than the sum of its proper divisors (1).

27172697681 is an equidigital number, since it uses as much as digits as its factorization.

27172697681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3556224, while the sum is 56.

The spelling of 27172697681 in words is "twenty-seven billion, one hundred seventy-two million, six hundred ninety-seven thousand, six hundred eighty-one".