261421 has 4 divisors (see below), whose sum is σ = 275200. Its totient is φ = 247644.

The previous prime is 261407. The next prime is 261427. The reversal of 261421 is 124162.

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: 124162 = 2 ⋅62081.

It is a cyclic number.

It is not a de Polignac number, because 261421 - 2⁵ = 261389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261395 and 261404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261427) 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, 6861 + ... + 6898.

It is an arithmetic number, because the mean of its divisors is an integer number (68800).

2²⁶¹⁴²¹ is an apocalyptic number.

It is an amenable number.

261421 is a deficient number, since it is larger than the sum of its proper divisors (13779).

261421 is a wasteful number, since it uses less digits than its factorization.

261421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13778.

The product of its digits is 96, while the sum is 16.

The square root of 261421 is about 511.2934578107. The cubic root of 261421 is about 63.9411079342.

Adding to 261421 its reverse (124162), we get a palindrome (385583).

The spelling of 261421 in words is "two hundred sixty-one thousand, four hundred twenty-one".