261651853 has 2 divisors, whose sum is σ = 261651854. Its totient is φ = 261651852.

The previous prime is 261651829. The next prime is 261651883. The reversal of 261651853 is 358156162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 175774564 + 85877289 = 13258^2 + 9267^2 .

It is a cyclic number.

It is not a de Polignac number, because 261651853 - 2⁵ = 261651821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261651883) 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, 130825926 + 130825927.

It is an arithmetic number, because the mean of its divisors is an integer number (130825927).

Almost surely, 2^261651853 is an apocalyptic number.

It is an amenable number.

261651853 is a deficient number, since it is larger than the sum of its proper divisors (1).

261651853 is an equidigital number, since it uses as much as digits as its factorization.

261651853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43200, while the sum is 37.

The square root of 261651853 is about 16175.6561845262. The cubic root of 261651853 is about 639.5992388461.

The spelling of 261651853 in words is "two hundred sixty-one million, six hundred fifty-one thousand, eight hundred fifty-three".