1803121645 has 8 divisors (see below), whose sum is σ = 2330188056. Its totient is φ = 1331535936.

The previous prime is 1803121637. The next prime is 1803121669. The reversal of 1803121645 is 5461213081.

It can be written as a sum of positive squares in 4 ways, for example, as 227587396 + 1575534249 = 15086^2 + 39693^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1803121645 - 2³ = 1803121637 is a prime.

It is a super-3 number, since 3×1803121645³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13870102 + ... + 13870231.

It is an arithmetic number, because the mean of its divisors is an integer number (291273507).

Almost surely, 2^1803121645 is an apocalyptic number.

It is an amenable number.

1803121645 is a deficient number, since it is larger than the sum of its proper divisors (527066411).

1803121645 is a wasteful number, since it uses less digits than its factorization.

1803121645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27740351.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 1803121645 is about 42463.1798738625. The cubic root of 1803121645 is about 1217.1431957911.

The spelling of 1803121645 in words is "one billion, eight hundred three million, one hundred twenty-one thousand, six hundred forty-five".