1821411685 has 16 divisors (see below), whose sum is σ = 2224370736. Its totient is φ = 1431502848.

The previous prime is 1821411661. The next prime is 1821411689. The reversal of 1821411685 is 5861141281.

It is a Cunningham number, because it is equal to 42678²+1.

It can be written as a sum of positive squares in 8 ways, for example, as 9972964 + 1811438721 = 3158^2 + 42561^2 .

It is a cyclic number.

It is not a de Polignac number, because 1821411685 - 2¹⁵ = 1821378917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821411689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84097 + ... + 103513.

It is an arithmetic number, because the mean of its divisors is an integer number (139023171).

Almost surely, 2^1821411685 is an apocalyptic number.

It is an amenable number.

1821411685 is a deficient number, since it is larger than the sum of its proper divisors (402959051).

1821411685 is a wasteful number, since it uses less digits than its factorization.

1821411685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19752.

The product of its digits is 15360, while the sum is 37.

The square root of 1821411685 is about 42678.0000117156. Note that the first 4 decimals coincide. The cubic root of 1821411685 is about 1221.2447398438.

The spelling of 1821411685 in words is "one billion, eight hundred twenty-one million, four hundred eleven thousand, six hundred eighty-five".