189621521 has 4 divisors (see below), whose sum is σ = 189659700. Its totient is φ = 189583344.

The previous prime is 189621503. The next prime is 189621527. The reversal of 189621521 is 125126981.

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 98227921 + 91393600 = 9911^2 + 9560^2 .

It is a cyclic number.

It is not a de Polignac number, because 189621521 - 2²² = 185427217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (189621527) 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, 10286 + ... + 22023.

It is an arithmetic number, because the mean of its divisors is an integer number (47414925).

Almost surely, 2^189621521 is an apocalyptic number.

It is an amenable number.

189621521 is a deficient number, since it is larger than the sum of its proper divisors (38179).

189621521 is an equidigital number, since it uses as much as digits as its factorization.

189621521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38178.

The product of its digits is 8640, while the sum is 35.

The square root of 189621521 is about 13770.3130320265. The cubic root of 189621521 is about 574.5077283909.

The spelling of 189621521 in words is "one hundred eighty-nine million, six hundred twenty-one thousand, five hundred twenty-one".