261630625 has 15 divisors (see below), whose sum is σ = 327439717. Its totient is φ = 208981000.

The previous prime is 261630601. The next prime is 261630637. The reversal of 261630625 is 526036162.

The square root of 261630625 is 16175.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20511841 + 241118784 = 4529^2 + 15528^2 .

It is not a de Polignac number, because 261630625 - 2⁹ = 261630113 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 404052 + ... + 404698.

Almost surely, 2^261630625 is an apocalyptic number.

261630625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261630625 is the 16175-th square number.

261630625 is the 8088-th centered octagonal number.

It is an amenable number.

261630625 is a deficient number, since it is larger than the sum of its proper divisors (65809092).

261630625 is an frugal number, since it uses more digits than its factorization.

261630625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1314 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 31.

The cubic root of 261630625 is about 639.5819413320.

Adding to 261630625 its reverse (526036162), we get a palindrome (787666787).

The spelling of 261630625 in words is "two hundred sixty-one million, six hundred thirty thousand, six hundred twenty-five".