206501561 has 16 divisors (see below), whose sum is σ = 238323840. Its totient is φ = 175271040.

The previous prime is 206501549. The next prime is 206501563. The reversal of 206501561 is 165105602.

It is not a de Polignac number, because 206501561 - 2¹⁸ = 206239417 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 206501561.

It is not an unprimeable number, because it can be changed into a prime (206501563) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 544670 + ... + 545048.

It is an arithmetic number, because the mean of its divisors is an integer number (14895240).

Almost surely, 2^206501561 is an apocalyptic number.

It is an amenable number.

206501561 is a deficient number, since it is larger than the sum of its proper divisors (31822279).

206501561 is a wasteful number, since it uses less digits than its factorization.

206501561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 206501561 is about 14370.1621772338. The cubic root of 206501561 is about 591.0729885625.

The spelling of 206501561 in words is "two hundred six million, five hundred one thousand, five hundred sixty-one".