205355661 has 32 divisors (see below), whose sum is σ = 335382528. Its totient is φ = 109200960.

The previous prime is 205355653. The next prime is 205355669. The reversal of 205355661 is 166553502.

It is an interprime number because it is at equal distance from previous prime (205355653) and next prime (205355669).

It is not a de Polignac number, because 205355661 - 2³ = 205355653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205355669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12126 + ... + 23616.

It is an arithmetic number, because the mean of its divisors is an integer number (10480704).

Almost surely, 2^205355661 is an apocalyptic number.

205355661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

205355661 is a deficient number, since it is larger than the sum of its proper divisors (130026867).

205355661 is a wasteful number, since it uses less digits than its factorization.

205355661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11561.

The product of its (nonzero) digits is 27000, while the sum is 33.

The square root of 205355661 is about 14330.2359017568. The cubic root of 205355661 is about 589.9776502115.

The spelling of 205355661 in words is "two hundred five million, three hundred fifty-five thousand, six hundred sixty-one".