191421 has 6 divisors (see below), whose sum is σ = 276510. Its totient is φ = 127608.

The previous prime is 191413. The next prime is 191441. The reversal of 191421 is 124191.

191421 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 168921 + 22500 = 411^2 + 150^2 .

It is not a de Polignac number, because 191421 - 2³ = 191413 is a prime.

191421 is strictly pandigital in base 7.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 191394 and 191403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191441) 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 5 ways as a sum of consecutive naturals, for example, 10626 + ... + 10643.

It is an arithmetic number, because the mean of its divisors is an integer number (46085).

2¹⁹¹⁴²¹ is an apocalyptic number.

It is an amenable number.

191421 is a deficient number, since it is larger than the sum of its proper divisors (85089).

191421 is a wasteful number, since it uses less digits than its factorization.

191421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21275 (or 21272 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

The square root of 191421 is about 437.5168568181. The cubic root of 191421 is about 57.6319339705.

The spelling of 191421 in words is "one hundred ninety-one thousand, four hundred twenty-one".