261400625 has 30 divisors (see below), whose sum is σ = 337959006. Its totient is φ = 202000000.

The previous prime is 261400583. The next prime is 261400627. The reversal of 261400625 is 526004162.

It can be written as a sum of positive squares in 15 ways, for example, as 219306481 + 42094144 = 14809^2 + 6488^2 .

It is not a de Polignac number, because 261400625 - 2⁶ = 261400561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261400594 and 261400603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261400627) by changing a digit.

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 29 ways as a sum of consecutive naturals, for example, 2588075 + ... + 2588175.

Almost surely, 2^261400625 is an apocalyptic number.

261400625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261400625 is a deficient number, since it is larger than the sum of its proper divisors (76558381).

261400625 is an frugal number, since it uses more digits than its factorization.

261400625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263 (or 147 counting only the distinct ones).

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

The square root of 261400625 is about 16167.8886995179. Note that the first 3 decimals coincide. The cubic root of 261400625 is about 639.3944671350.

Adding to 261400625 its reverse (526004162), we get a palindrome (787404787).

The spelling of 261400625 in words is "two hundred sixty-one million, four hundred thousand, six hundred twenty-five".