205191025 has 12 divisors (see below), whose sum is σ = 274009372. Its totient is φ = 151525440.

The previous prime is 205191001. The next prime is 205191047. The reversal of 205191025 is 520191502.

It can be written as a sum of positive squares in 6 ways, for example, as 815409 + 204375616 = 903^2 + 14296^2 .

It is a de Polignac number, because none of the positive numbers 2^k-205191025 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 315354 + ... + 316003.

Almost surely, 2^205191025 is an apocalyptic number.

205191025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

205191025 is a deficient number, since it is larger than the sum of its proper divisors (68818347).

205191025 is a wasteful number, since it uses less digits than its factorization.

205191025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631380 (or 631375 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 205191025 is about 14324.4903923316. The cubic root of 205191025 is about 589.8199440986.

The spelling of 205191025 in words is "two hundred five million, one hundred ninety-one thousand, twenty-five".