261220520123 has 4 divisors (see below), whose sum is σ = 261239148888. Its totient is φ = 261201891360.

The previous prime is 261220520117. The next prime is 261220520161. The reversal of 261220520123 is 321025022162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261220520123 - 2⁴ = 261220520107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261220520092 and 261220520101.

It is not an unprimeable number, because it can be changed into a prime (261220520173) 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, 9293333 + ... + 9321398.

It is an arithmetic number, because the mean of its divisors is an integer number (65309787222).

Almost surely, 2^261220520123 is an apocalyptic number.

261220520123 is a deficient number, since it is larger than the sum of its proper divisors (18628765).

261220520123 is a wasteful number, since it uses less digits than its factorization.

261220520123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18628764.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 261220520123 its reverse (321025022162), we get a palindrome (582245542285).

The spelling of 261220520123 in words is "two hundred sixty-one billion, two hundred twenty million, five hundred twenty thousand, one hundred twenty-three".