2781621836 has 12 divisors (see below), whose sum is σ = 5563243728. Its totient is φ = 1192123632.

The previous prime is 2781621823. The next prime is 2781621839. The reversal of 2781621836 is 6381261872.

2781621836 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (2781621839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49671791 + ... + 49671846.

It is an arithmetic number, because the mean of its divisors is an integer number (463603644).

Almost surely, 2^2781621836 is an apocalyptic number.

It is an amenable number.

2781621836 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2781621836 is a wasteful number, since it uses less digits than its factorization.

2781621836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99343648 (or 99343646 counting only the distinct ones).

The product of its digits is 193536, while the sum is 44.

The square root of 2781621836 is about 52741.0829998778. The cubic root of 2781621836 is about 1406.3692508031.

The spelling of 2781621836 in words is "two billion, seven hundred eighty-one million, six hundred twenty-one thousand, eight hundred thirty-six".