205869640 has 16 divisors (see below), whose sum is σ = 463206780. Its totient is φ = 82347840.

The previous prime is 205869583. The next prime is 205869641. The reversal of 205869640 is 46968502.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 205119684 + 749956 = 14322^2 + 866^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 5146741 = 205869640 / (2 + 0 + 5 + 8 + 6 + 9 + 6 + 4 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 205869593 and 205869602.

It is not an unprimeable number, because it can be changed into a prime (205869641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2573331 + ... + 2573410.

Almost surely, 2^205869640 is an apocalyptic number.

205869640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205869640 is an abundant number, since it is smaller than the sum of its proper divisors (257337140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205869640 is a wasteful number, since it uses less digits than its factorization.

205869640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5146752 (or 5146748 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 205869640 is about 14348.1580699405. The cubic root of 205869640 is about 590.4694530432.

The spelling of 205869640 in words is "two hundred five million, eight hundred sixty-nine thousand, six hundred forty".