261404137 has 2 divisors, whose sum is σ = 261404138. Its totient is φ = 261404136.

The previous prime is 261404123. The next prime is 261404197. The reversal of 261404137 is 731404162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130782096 + 130622041 = 11436^2 + 11429^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261404137 is a prime.

It is not a weakly prime, because it can be changed into another prime (261404107) 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, 130702068 + 130702069.

It is an arithmetic number, because the mean of its divisors is an integer number (130702069).

Almost surely, 2^261404137 is an apocalyptic number.

It is an amenable number.

261404137 is a deficient number, since it is larger than the sum of its proper divisors (1).

261404137 is an equidigital number, since it uses as much as digits as its factorization.

261404137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 261404137 is about 16167.9973095000. The cubic root of 261404137 is about 639.3973306111.

Adding to 261404137 its reverse (731404162), we get a palindrome (992808299).

The spelling of 261404137 in words is "two hundred sixty-one million, four hundred four thousand, one hundred thirty-seven".