201671521 has 4 divisors (see below), whose sum is σ = 210439872. Its totient is φ = 192903172.

The previous prime is 201671489. The next prime is 201671537. The reversal of 201671521 is 125176102.

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, and also an emirpimes, since its reverse is a distinct semiprime: 125176102 = 2 ⋅62588051.

It is a cyclic number.

It is not a de Polignac number, because 201671521 - 2⁵ = 201671489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (201671581) 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, 4384141 + ... + 4384186.

It is an arithmetic number, because the mean of its divisors is an integer number (52609968).

Almost surely, 2^201671521 is an apocalyptic number.

It is an amenable number.

201671521 is a deficient number, since it is larger than the sum of its proper divisors (8768351).

201671521 is an equidigital number, since it uses as much as digits as its factorization.

201671521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8768350.

The product of its (nonzero) digits is 840, while the sum is 25.

The square root of 201671521 is about 14201.1098509940. The cubic root of 201671521 is about 586.4282155873.

It can be divided in two parts, 2016 and 71521, that added together give a palindrome (73537).

The spelling of 201671521 in words is "two hundred one million, six hundred seventy-one thousand, five hundred twenty-one".