20105904899837 has 4 divisors (see below), whose sum is σ = 20193703611420. Its totient is φ = 20018106188256.

The previous prime is 20105904899833. The next prime is 20105904899881. The reversal of 20105904899837 is 73899840950102.

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 19227821582116 + 878083317721 = 4384954^2 + 937061^2 .

It is a cyclic number.

It is not a de Polignac number, because 20105904899837 - 2² = 20105904899833 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 (20105904899833) 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, 43899355448 + ... + 43899355905.

It is an arithmetic number, because the mean of its divisors is an integer number (5048425902855).

Almost surely, 2^{20105904899837} is an apocalyptic number.

It is an amenable number.

20105904899837 is a deficient number, since it is larger than the sum of its proper divisors (87798711583).

20105904899837 is an equidigital number, since it uses as much as digits as its factorization.

20105904899837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87798711582.

The product of its (nonzero) digits is 39191040, while the sum is 65.

The spelling of 20105904899837 in words is "twenty trillion, one hundred five billion, nine hundred four million, eight hundred ninety-nine thousand, eight hundred thirty-seven".