1878644378821 has 16 divisors (see below), whose sum is σ = 2225581050240. Its totient is φ = 1551573616320.

The previous prime is 1878644378801. The next prime is 1878644378827. The reversal of 1878644378821 is 1288734468781.

It is not a de Polignac number, because 1878644378821 - 2⁵ = 1878644378789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1878644378827) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9324366 + ... + 9523711.

It is an arithmetic number, because the mean of its divisors is an integer number (139098815640).

Almost surely, 2^{1878644378821} is an apocalyptic number.

It is an amenable number.

1878644378821 is a deficient number, since it is larger than the sum of its proper divisors (346936671419).

1878644378821 is a wasteful number, since it uses less digits than its factorization.

1878644378821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18848604.

The product of its digits is 115605504, while the sum is 67.

The spelling of 1878644378821 in words is "one trillion, eight hundred seventy-eight billion, six hundred forty-four million, three hundred seventy-eight thousand, eight hundred twenty-one".