7878619881 has 18 divisors (see below), whose sum is σ = 12508848170. Its totient is φ = 4774920480.

The previous prime is 7878619877. The next prime is 7878619907. The reversal of 7878619881 is 1889168787.

7878619881 is a `hidden beast` number, since 7 + 8 + 7 + 8 + 619 + 8 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5661057600 + 2217562281 = 75240^2 + 47091^2 .

It is not a de Polignac number, because 7878619881 - 2² = 7878619877 is a prime.

It is a super-2 number, since 2×7878619881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7878619481) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3616276 + ... + 3618453.

Almost surely, 2^7878619881 is an apocalyptic number.

It is an amenable number.

7878619881 is a deficient number, since it is larger than the sum of its proper divisors (4630228289).

7878619881 is a wasteful number, since it uses less digits than its factorization.

7878619881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7234757 (or 7234743 counting only the distinct ones).

The product of its digits is 10838016, while the sum is 63.

The square root of 7878619881 is about 88761.5901220793. The cubic root of 7878619881 is about 1989.8333977509.

The spelling of 7878619881 in words is "seven billion, eight hundred seventy-eight million, six hundred nineteen thousand, eight hundred eighty-one".