20845618537 has 4 divisors (see below), whose sum is σ = 21079839060. Its totient is φ = 20611398016.

The previous prime is 20845618513. The next prime is 20845618559. The reversal of 20845618537 is 73581654802.

It is a happy number.

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 10831813776 + 10013804761 = 104076^2 + 100069^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20845618537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20845618567) 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, 117110128 + ... + 117110305.

It is an arithmetic number, because the mean of its divisors is an integer number (5269959765).

Almost surely, 2^20845618537 is an apocalyptic number.

It is an amenable number.

20845618537 is a deficient number, since it is larger than the sum of its proper divisors (234220523).

20845618537 is an equidigital number, since it uses as much as digits as its factorization.

20845618537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234220522.

The product of its (nonzero) digits is 1612800, while the sum is 49.

The spelling of 20845618537 in words is "twenty billion, eight hundred forty-five million, six hundred eighteen thousand, five hundred thirty-seven".