2078388663881 has 4 divisors (see below), whose sum is σ = 2078812052100. Its totient is φ = 2077965275664.

The previous prime is 2078388663877. The next prime is 2078388663889. The reversal of 2078388663881 is 1883668838702.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2022069780025 + 56318883856 = 1421995^2 + 237316^2 .

It is a cyclic number.

It is not a de Polignac number, because 2078388663881 - 2² = 2078388663877 is a prime.

It is a super-2 number, since 2×2078388663881² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2078388663889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 211686746 + ... + 211696563.

It is an arithmetic number, because the mean of its divisors is an integer number (519703013025).

Almost surely, 2^{2078388663881} is an apocalyptic number.

It is an amenable number.

2078388663881 is a deficient number, since it is larger than the sum of its proper divisors (423388219).

2078388663881 is an equidigital number, since it uses as much as digits as its factorization.

2078388663881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423388218.

The product of its (nonzero) digits is 148635648, while the sum is 68.

The spelling of 2078388663881 in words is "two trillion, seventy-eight billion, three hundred eighty-eight million, six hundred sixty-three thousand, eight hundred eighty-one".