1981800511 has 2 divisors, whose sum is σ = 1981800512. Its totient is φ = 1981800510.

The previous prime is 1981800439. The next prime is 1981800533. The reversal of 1981800511 is 1150081891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1981800511 - 2¹⁵ = 1981767743 is a prime.

It is a super-2 number, since 2×1981800511² = 7855066530799722242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981800011) 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 as a sum of consecutive naturals, namely, 990900255 + 990900256.

It is an arithmetic number, because the mean of its divisors is an integer number (990900256).

Almost surely, 2^1981800511 is an apocalyptic number.

1981800511 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981800511 is an equidigital number, since it uses as much as digits as its factorization.

1981800511 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 34.

The square root of 1981800511 is about 44517.4180630458. The cubic root of 1981800511 is about 1256.0877456972.

The spelling of 1981800511 in words is "one billion, nine hundred eighty-one million, eight hundred thousand, five hundred eleven".