201540561 has 4 divisors (see below), whose sum is σ = 268720752. Its totient is φ = 134360372.

The previous prime is 201540553. The next prime is 201540569. The reversal of 201540561 is 165045102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (201540553) and next prime (201540569).

It is a cyclic number.

It is not a de Polignac number, because 201540561 - 2³ = 201540553 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (201540569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33590091 + ... + 33590096.

It is an arithmetic number, because the mean of its divisors is an integer number (67180188).

Almost surely, 2^201540561 is an apocalyptic number.

It is an amenable number.

201540561 is a deficient number, since it is larger than the sum of its proper divisors (67180191).

201540561 is an equidigital number, since it uses as much as digits as its factorization.

201540561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67180190.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 201540561 is about 14196.4981949775. The cubic root of 201540561 is about 586.3012512571.

Adding to 201540561 its reverse (165045102), we get a palindrome (366585663).

The spelling of 201540561 in words is "two hundred one million, five hundred forty thousand, five hundred sixty-one".