201521 has 4 divisors (see below), whose sum is σ = 208500. Its totient is φ = 194544.

The previous prime is 201517. The next prime is 201547. The reversal of 201521 is 125102.

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 144400 + 57121 = 380^2 + 239^2 .

It is a cyclic number.

It is not a de Polignac number, because 201521 - 2² = 201517 is a prime.

It is a super-2 number, since 2×201521² = 81221426882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (201511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3446 + ... + 3503.

It is an arithmetic number, because the mean of its divisors is an integer number (52125).

2²⁰¹⁵²¹ is an apocalyptic number.

It is an amenable number.

201521 is a deficient number, since it is larger than the sum of its proper divisors (6979).

201521 is an equidigital number, since it uses as much as digits as its factorization.

201521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6978.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 201521 is about 448.9109043006. The cubic root of 201521 is about 58.6282282354.

Adding to 201521 its reverse (125102), we get a palindrome (326623).

The spelling of 201521 in words is "two hundred one thousand, five hundred twenty-one".