261876804121 has 9 divisors (see below), whose sum is σ = 263700383583. Its totient is φ = 260065759800.

The previous prime is 261876804107. The next prime is 261876804127. The reversal of 261876804121 is 121408678162.

The square root of 261876804121 is 511739.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 254206547721 + 7670256400 = 504189^2 + 87580^2 .

It is not a de Polignac number, because 261876804121 - 2²⁹ = 261339933209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261876804127) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 77270895 + ... + 77274283.

Almost surely, 2^261876804121 is an apocalyptic number.

261876804121 is the 511739-th square number.

261876804121 is the 255870-th centered octagonal number.

It is an amenable number.

261876804121 is a deficient number, since it is larger than the sum of its proper divisors (1823579462).

261876804121 is an frugal number, since it uses more digits than its factorization.

261876804121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7080 (or 3540 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 46.

The spelling of 261876804121 in words is "two hundred sixty-one billion, eight hundred seventy-six million, eight hundred four thousand, one hundred twenty-one".