2664818581 has 2 divisors, whose sum is σ = 2664818582. Its totient is φ = 2664818580.

The previous prime is 2664818579. The next prime is 2664818627. The reversal of 2664818581 is 1858184662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1443316081 + 1221502500 = 37991^2 + 34950^2 .

It is a cyclic number.

It is not a de Polignac number, because 2664818581 - 2¹ = 2664818579 is a prime.

It is a super-2 number, since 2×2664818581² = 14202516139285707122, which contains 22 as substring.

Together with 2664818579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2664818281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332409290 + 1332409291.

It is an arithmetic number, because the mean of its divisors is an integer number (1332409291).

Almost surely, 2^2664818581 is an apocalyptic number.

It is an amenable number.

2664818581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2664818581 is an equidigital number, since it uses as much as digits as its factorization.

2664818581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 737280, while the sum is 49.

The square root of 2664818581 is about 51621.8808355527. The cubic root of 2664818581 is about 1386.4021269108.

The spelling of 2664818581 in words is "two billion, six hundred sixty-four million, eight hundred eighteen thousand, five hundred eighty-one".