1878685821 has 12 divisors (see below), whose sum is σ = 2722922748. Its totient is φ = 1248180864.

The previous prime is 1878685817. The next prime is 1878685849. The reversal of 1878685821 is 1285868781.

It can be written as a sum of positive squares in 2 ways, for example, as 1631756025 + 246929796 = 40395^2 + 15714^2 .

It is not a de Polignac number, because 1878685821 - 2² = 1878685817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1878685891) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 353580 + ... + 358853.

It is an arithmetic number, because the mean of its divisors is an integer number (226910229).

Almost surely, 2^1878685821 is an apocalyptic number.

It is an amenable number.

1878685821 is a deficient number, since it is larger than the sum of its proper divisors (844236927).

1878685821 is a wasteful number, since it uses less digits than its factorization.

1878685821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 712732 (or 712729 counting only the distinct ones).

The product of its digits is 1720320, while the sum is 54.

The square root of 1878685821 is about 43343.8094887840. The cubic root of 1878685821 is about 1233.9135097388.

The spelling of 1878685821 in words is "one billion, eight hundred seventy-eight million, six hundred eighty-five thousand, eight hundred twenty-one".