261878629 has 2 divisors, whose sum is σ = 261878630. Its totient is φ = 261878628.

The previous prime is 261878623. The next prime is 261878657. The reversal of 261878629 is 926878162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261630625 + 248004 = 16175^2 + 498^2 .

It is a cyclic number.

It is not a de Polignac number, because 261878629 - 2¹³ = 261870437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261878623) 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, 130939314 + 130939315.

It is an arithmetic number, because the mean of its divisors is an integer number (130939315).

Almost surely, 2^261878629 is an apocalyptic number.

It is an amenable number.

261878629 is a deficient number, since it is larger than the sum of its proper divisors (1).

261878629 is an equidigital number, since it uses as much as digits as its factorization.

261878629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 49.

The square root of 261878629 is about 16182.6644592292. The cubic root of 261878629 is about 639.7839676137.

The spelling of 261878629 in words is "two hundred sixty-one million, eight hundred seventy-eight thousand, six hundred twenty-nine".