1821310491 has 32 divisors (see below), whose sum is σ = 3260533248. Its totient is φ = 873354240.

The previous prime is 1821310441. The next prime is 1821310511. The reversal of 1821310491 is 1940131281.

It is not a de Polignac number, because 1821310491 - 2¹¹ = 1821308443 is a prime.

It is a super-2 number, since 2×1821310491² = 6634343809253322162, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1821310441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 300246 + ... + 306251.

It is an arithmetic number, because the mean of its divisors is an integer number (101891664).

Almost surely, 2^1821310491 is an apocalyptic number.

1821310491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1821310491 is a deficient number, since it is larger than the sum of its proper divisors (1439222757).

1821310491 is a wasteful number, since it uses less digits than its factorization.

1821310491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606531.

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 1821310491 is about 42676.8144429736. The cubic root of 1821310491 is about 1221.2221227844. Note that the first 3 decimals are identical.

The spelling of 1821310491 in words is "one billion, eight hundred twenty-one million, three hundred ten thousand, four hundred ninety-one".