1821861812 has 12 divisors (see below), whose sum is σ = 3188648736. Its totient is φ = 910819320.

The previous prime is 1821861791. The next prime is 1821861817. The reversal of 1821861812 is 2181681281.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821861817) 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, 16793 + ... + 62655.

It is an arithmetic number, because the mean of its divisors is an integer number (265720728).

Almost surely, 2^1821861812 is an apocalyptic number.

It is an amenable number.

1821861812 is a deficient number, since it is larger than the sum of its proper divisors (1366786924).

1821861812 is a wasteful number, since it uses less digits than its factorization.

1821861812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55798 (or 55796 counting only the distinct ones).

The product of its digits is 12288, while the sum is 38.

The square root of 1821861812 is about 42683.2732109429. The cubic root of 1821861812 is about 1221.3453339705.

The spelling of 1821861812 in words is "one billion, eight hundred twenty-one million, eight hundred sixty-one thousand, eight hundred twelve".