261621925 has 48 divisors (see below), whose sum is σ = 365601600. Its totient is φ = 184550400.

The previous prime is 261621889. The next prime is 261621929. The reversal of 261621925 is 529126162.

It is a happy number.

It is not a de Polignac number, because 261621925 - 2¹⁵ = 261589157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261621929) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1445335 + ... + 1445515.

It is an arithmetic number, because the mean of its divisors is an integer number (7616700).

Almost surely, 2^261621925 is an apocalyptic number.

261621925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261621925 is a deficient number, since it is larger than the sum of its proper divisors (103979675).

261621925 is a wasteful number, since it uses less digits than its factorization.

261621925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406 (or 401 counting only the distinct ones).

The product of its digits is 12960, while the sum is 34.

The square root of 261621925 is about 16174.7310642248. The cubic root of 261621925 is about 639.5748519166.

The spelling of 261621925 in words is "two hundred sixty-one million, six hundred twenty-one thousand, nine hundred twenty-five".