2155447681 has 2 divisors, whose sum is σ = 2155447682. Its totient is φ = 2155447680.

The previous prime is 2155447673. The next prime is 2155447703. The reversal of 2155447681 is 1867445512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1307473281 + 847974400 = 36159^2 + 29120^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155447681 - 2³ = 2155447673 is a prime.

It is a super-2 number, since 2×2155447681² = 9291909411056555522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2155447601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1077723840 + 1077723841.

It is an arithmetic number, because the mean of its divisors is an integer number (1077723841).

Almost surely, 2^2155447681 is an apocalyptic number.

It is an amenable number.

2155447681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2155447681 is an equidigital number, since it uses as much as digits as its factorization.

2155447681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 268800, while the sum is 43.

The square root of 2155447681 is about 46426.7991681529. The cubic root of 2155447681 is about 1291.7520573410.

The spelling of 2155447681 in words is "two billion, one hundred fifty-five million, four hundred forty-seven thousand, six hundred eighty-one".