261828421 has 4 divisors (see below), whose sum is σ = 261865600. Its totient is φ = 261791244.

The previous prime is 261828403. The next prime is 261828451. The reversal of 261828421 is 124828162.

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.

It is a cyclic number.

It is not a de Polignac number, because 261828421 - 2⁷ = 261828293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261828451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4431 + ... + 23308.

It is an arithmetic number, because the mean of its divisors is an integer number (65466400).

Almost surely, 2^261828421 is an apocalyptic number.

It is an amenable number.

261828421 is a deficient number, since it is larger than the sum of its proper divisors (37179).

261828421 is an equidigital number, since it uses as much as digits as its factorization.

261828421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37178.

The product of its digits is 12288, while the sum is 34.

The square root of 261828421 is about 16181.1130952107. The cubic root of 261828421 is about 639.7430780272.

The spelling of 261828421 in words is "two hundred sixty-one million, eight hundred twenty-eight thousand, four hundred twenty-one".