261105670225 has 9 divisors (see below), whose sum is σ = 323774199217. Its totient is φ = 208882492240.

The previous prime is 261105670223. The next prime is 261105670247. The reversal of 261105670225 is 522076501162.

The square root of 261105670225 is 510985.

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

It can be written as a sum of positive squares in 4 ways, for example, as 8032282129 + 253073388096 = 89623^2 + 503064^2 .

It is not a de Polignac number, because 261105670225 - 2¹ = 261105670223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261105670223) 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, 2503827 + ... + 2606023.

Almost surely, 2^261105670225 is an apocalyptic number.

261105670225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261105670225 is the 510985-th square number.

261105670225 is the 255493-rd centered octagonal number.

It is an amenable number.

261105670225 is a deficient number, since it is larger than the sum of its proper divisors (62668528992).

261105670225 is an frugal number, since it uses more digits than its factorization.

261105670225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204404 (or 102202 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 37.

The spelling of 261105670225 in words is "two hundred sixty-one billion, one hundred five million, six hundred seventy thousand, two hundred twenty-five".