20506401760261 has 4 divisors (see below), whose sum is σ = 20506449775500. Its totient is φ = 20506353745024.

The previous prime is 20506401760193. The next prime is 20506401760289. The reversal of 20506401760261 is 16206710460502.

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 17083879560225 + 3422522200036 = 4133265^2 + 1850006^2 .

It is a cyclic number.

It is not a de Polignac number, because 20506401760261 - 2⁹ = 20506401759749 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 (20506401760561) 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, 23361196 + ... + 24223093.

It is an arithmetic number, because the mean of its divisors is an integer number (5126612443875).

Almost surely, 2^{20506401760261} is an apocalyptic number.

It is an amenable number.

20506401760261 is a deficient number, since it is larger than the sum of its proper divisors (48015239).

20506401760261 is an equidigital number, since it uses as much as digits as its factorization.

20506401760261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48015238.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 20506401760261 in words is "twenty trillion, five hundred six billion, four hundred one million, seven hundred sixty thousand, two hundred sixty-one".