261442421 has 2 divisors, whose sum is σ = 261442422. Its totient is φ = 261442420.

The previous prime is 261442417. The next prime is 261442469. The reversal of 261442421 is 124244162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 226502500 + 34939921 = 15050^2 + 5911^2 .

It is a cyclic number.

It is not a de Polignac number, because 261442421 - 2² = 261442417 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261442471) 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 as a sum of consecutive naturals, namely, 130721210 + 130721211.

It is an arithmetic number, because the mean of its divisors is an integer number (130721211).

Almost surely, 2^261442421 is an apocalyptic number.

It is an amenable number.

261442421 is a deficient number, since it is larger than the sum of its proper divisors (1).

261442421 is an equidigital number, since it uses as much as digits as its factorization.

261442421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3072, while the sum is 26.

The square root of 261442421 is about 16169.1812099438. The cubic root of 261442421 is about 639.4285434460.

Adding to 261442421 its reverse (124244162), we get a palindrome (385686583).

The spelling of 261442421 in words is "two hundred sixty-one million, four hundred forty-two thousand, four hundred twenty-one".