2661133681 has 2 divisors, whose sum is σ = 2661133682. Its totient is φ = 2661133680.

The previous prime is 2661133663. The next prime is 2661133687. The reversal of 2661133681 is 1863311662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2218410000 + 442723681 = 47100^2 + 21041^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661133681 - 2⁹ = 2661133169 is a prime.

It is a super-2 number, since 2×2661133681² = 14163264936305219522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2661133681.

It is not a weakly prime, because it can be changed into another prime (2661133687) 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, 1330566840 + 1330566841.

It is an arithmetic number, because the mean of its divisors is an integer number (1330566841).

Almost surely, 2^2661133681 is an apocalyptic number.

It is an amenable number.

2661133681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661133681 is an equidigital number, since it uses as much as digits as its factorization.

2661133681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 37.

The square root of 2661133681 is about 51586.1772280133. The cubic root of 2661133681 is about 1385.7627951088.

The spelling of 2661133681 in words is "two billion, six hundred sixty-one million, one hundred thirty-three thousand, six hundred eighty-one".