1820121544445 has 4 divisors (see below), whose sum is σ = 2184145853340. Its totient is φ = 1456097235552.

The previous prime is 1820121544403. The next prime is 1820121544453. The reversal of 1820121544445 is 5444451210281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 892870026724 + 927251517721 = 944918^2 + 962939^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820121544445 - 2¹⁴ = 1820121528061 is a prime.

It is a super-2 number, since 2×1820121544445² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 182012154440 + ... + 182012154449.

It is an arithmetic number, because the mean of its divisors is an integer number (546036463335).

Almost surely, 2^{1820121544445} is an apocalyptic number.

It is an amenable number.

1820121544445 is a deficient number, since it is larger than the sum of its proper divisors (364024308895).

1820121544445 is an equidigital number, since it uses as much as digits as its factorization.

1820121544445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 364024308894.

The product of its (nonzero) digits is 204800, while the sum is 41.

The spelling of 1820121544445 in words is "one trillion, eight hundred twenty billion, one hundred twenty-one million, five hundred forty-four thousand, four hundred forty-five".