261663625 has 16 divisors (see below), whose sum is σ = 327010320. Its totient is φ = 209040000.

The previous prime is 261663601. The next prime is 261663631. The reversal of 261663625 is 526366162.

It can be written as a sum of positive squares in 8 ways, for example, as 98565184 + 163098441 = 9928^2 + 12771^2 .

It is not a de Polignac number, because 261663625 - 2²¹ = 259566473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 161821 + ... + 163429.

It is an arithmetic number, because the mean of its divisors is an integer number (20438145).

Almost surely, 2^261663625 is an apocalyptic number.

261663625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261663625 is a deficient number, since it is larger than the sum of its proper divisors (65346695).

261663625 is a wasteful number, since it uses less digits than its factorization.

261663625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2925 (or 2915 counting only the distinct ones).

The product of its digits is 77760, while the sum is 37.

The square root of 261663625 is about 16176.0200605711. The cubic root of 261663625 is about 639.6088307896.

It can be divided in two parts, 26166 and 3625, that added together give a cube (29791 = 31³).

The spelling of 261663625 in words is "two hundred sixty-one million, six hundred sixty-three thousand, six hundred twenty-five".