1820521135 has 4 divisors (see below), whose sum is σ = 2184625368. Its totient is φ = 1456416904.

The previous prime is 1820521133. The next prime is 1820521141. The reversal of 1820521135 is 5311250281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5311250281 = 61609 ⋅86209.

It is a cyclic number.

It is not a de Polignac number, because 1820521135 - 2¹ = 1820521133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820521133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182052109 + ... + 182052118.

It is an arithmetic number, because the mean of its divisors is an integer number (546156342).

Almost surely, 2^1820521135 is an apocalyptic number.

1820521135 is a deficient number, since it is larger than the sum of its proper divisors (364104233).

1820521135 is an equidigital number, since it uses as much as digits as its factorization.

1820521135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364104232.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 1820521135 is about 42667.5653746496. The cubic root of 1820521135 is about 1221.0456713938.

It can be divided in two parts, 18205 and 21135, that added together give a triangular number (39340 = T₂₈₀).

The spelling of 1820521135 in words is "one billion, eight hundred twenty million, five hundred twenty-one thousand, one hundred thirty-five".