201681569 has 4 divisors (see below), whose sum is σ = 202370196. Its totient is φ = 200992944.

The previous prime is 201681551. The next prime is 201681577. The reversal of 201681569 is 965186102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 171924544 + 29757025 = 13112^2 + 5455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201681569 is a prime.

It is a super-2 number, since 2×201681569² = 81350910548603522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201681539) 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, 343874 + ... + 344459.

It is an arithmetic number, because the mean of its divisors is an integer number (50592549).

Almost surely, 2^201681569 is an apocalyptic number.

It is an amenable number.

201681569 is a deficient number, since it is larger than the sum of its proper divisors (688627).

201681569 is an equidigital number, since it uses as much as digits as its factorization.

201681569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688626.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 201681569 is about 14201.4636217539. The cubic root of 201681569 is about 586.4379547461.

The spelling of 201681569 in words is "two hundred one million, six hundred eighty-one thousand, five hundred sixty-nine".