20438488261 has 4 divisors (see below), whose sum is σ = 20443128300. Its totient is φ = 20433848224.

The previous prime is 20438488247. The next prime is 20438488297. The reversal of 20438488261 is 16288483402.

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 4560976225 + 15877512036 = 67535^2 + 126006^2 .

It is a cyclic number.

It is not a de Polignac number, because 20438488261 - 2²¹ = 20436391109 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 (20438488241) 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, 2313406 + ... + 2322223.

It is an arithmetic number, because the mean of its divisors is an integer number (5110782075).

Almost surely, 2^20438488261 is an apocalyptic number.

It is an amenable number.

20438488261 is a deficient number, since it is larger than the sum of its proper divisors (4640039).

20438488261 is an equidigital number, since it uses as much as digits as its factorization.

20438488261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4640038.

The product of its (nonzero) digits is 589824, while the sum is 46.

The spelling of 20438488261 in words is "twenty billion, four hundred thirty-eight million, four hundred eighty-eight thousand, two hundred sixty-one".