1809649645537 has 4 divisors (see below), whose sum is σ = 1809723590596. Its totient is φ = 1809575700480.

The previous prime is 1809649645513. The next prime is 1809649645607. The reversal of 1809649645537 is 7355469469081.

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 579378246561 + 1230271398976 = 761169^2 + 1109176^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1809649645537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1809649615537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36935808 + ... + 36984769.

It is an arithmetic number, because the mean of its divisors is an integer number (452430897649).

Almost surely, 2^{1809649645537} is an apocalyptic number.

It is an amenable number.

1809649645537 is a deficient number, since it is larger than the sum of its proper divisors (73945059).

1809649645537 is an equidigital number, since it uses as much as digits as its factorization.

1809649645537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73945058.

The product of its (nonzero) digits is 195955200, while the sum is 67.

The spelling of 1809649645537 in words is "one trillion, eight hundred nine billion, six hundred forty-nine million, six hundred forty-five thousand, five hundred thirty-seven".