1821091869 has 16 divisors (see below), whose sum is σ = 2784944640. Its totient is φ = 1174897440.

The previous prime is 1821091849. The next prime is 1821091889. The reversal of 1821091869 is 9681901281.

It is an interprime number because it is at equal distance from previous prime (1821091849) and next prime (1821091889).

It is not a de Polignac number, because 1821091869 - 2¹¹ = 1821089821 is a prime.

It is a super-2 number, since 2×1821091869² = 6632751190675826322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821091829) 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, 1087032 + ... + 1088705.

It is an arithmetic number, because the mean of its divisors is an integer number (174059040).

Almost surely, 2^1821091869 is an apocalyptic number.

It is an amenable number.

1821091869 is a deficient number, since it is larger than the sum of its proper divisors (963852771).

1821091869 is a wasteful number, since it uses less digits than its factorization.

1821091869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175777 (or 2175771 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 45.

The square root of 1821091869 is about 42674.2529987345. The cubic root of 1821091869 is about 1221.1732574742.

The spelling of 1821091869 in words is "one billion, eight hundred twenty-one million, ninety-one thousand, eight hundred sixty-nine".