261532421 has 4 divisors (see below), whose sum is σ = 261611532. Its totient is φ = 261453312.

The previous prime is 261532363. The next prime is 261532441. The reversal of 261532421 is 124235162.

It is a happy number.

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 56040196 + 205492225 = 7486^2 + 14335^2 .

It is a cyclic number.

It is not a de Polignac number, because 261532421 - 2¹⁰ = 261531397 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 (261532441) 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, 34370 + ... + 41283.

It is an arithmetic number, because the mean of its divisors is an integer number (65402883).

Almost surely, 2^261532421 is an apocalyptic number.

It is an amenable number.

261532421 is a deficient number, since it is larger than the sum of its proper divisors (79111).

261532421 is an equidigital number, since it uses as much as digits as its factorization.

261532421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79110.

The product of its digits is 2880, while the sum is 26.

The square root of 261532421 is about 16171.9640427500. The cubic root of 261532421 is about 639.5019081871.

Adding to 261532421 its reverse (124235162), we get a palindrome (385767583).

The spelling of 261532421 in words is "two hundred sixty-one million, five hundred thirty-two thousand, four hundred twenty-one".