261218029 has 2 divisors, whose sum is σ = 261218030. Its totient is φ = 261218028.

The previous prime is 261217987. The next prime is 261218053. The reversal of 261218029 is 920812162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201696804 + 59521225 = 14202^2 + 7715^2 .

It is a cyclic number.

It is not a de Polignac number, because 261218029 - 2²¹ = 259120877 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 (261218129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130609014 + 130609015.

It is an arithmetic number, because the mean of its divisors is an integer number (130609015).

Almost surely, 2^261218029 is an apocalyptic number.

It is an amenable number.

261218029 is a deficient number, since it is larger than the sum of its proper divisors (1).

261218029 is an equidigital number, since it uses as much as digits as its factorization.

261218029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 261218029 is about 16162.2408409230. The cubic root of 261218029 is about 639.2455538628.

The spelling of 261218029 in words is "two hundred sixty-one million, two hundred eighteen thousand, twenty-nine".