201565531 has 4 divisors (see below), whose sum is σ = 201593992. Its totient is φ = 201537072.

The previous prime is 201565513. The next prime is 201565579. The reversal of 201565531 is 135565102.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 201565531 - 2⁵ = 201565499 is a prime.

It is a super-2 number, since 2×201565531² = 81257326574623922, which contains 22 as substring.

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 201565531.

It is not an unprimeable number, because it can be changed into a prime (201565501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5671 + ... + 20863.

It is an arithmetic number, because the mean of its divisors is an integer number (50398498).

Almost surely, 2^201565531 is an apocalyptic number.

201565531 is a deficient number, since it is larger than the sum of its proper divisors (28461).

201565531 is a wasteful number, since it uses less digits than its factorization.

201565531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28460.

The product of its (nonzero) digits is 4500, while the sum is 28.

The square root of 201565531 is about 14197.3776099673. The cubic root of 201565531 is about 586.3254636499.

The spelling of 201565531 in words is "two hundred one million, five hundred sixty-five thousand, five hundred thirty-one".