261651859 has 8 divisors (see below), whose sum is σ = 299936768. Its totient is φ = 223593480.

The previous prime is 261651853. The next prime is 261651883. The reversal of 261651859 is 958156162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261651859 - 2¹⁵ = 261619091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261651853) 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 in 7 ways as a sum of consecutive naturals, for example, 54147 + ... + 58780.

It is an arithmetic number, because the mean of its divisors is an integer number (37492096).

Almost surely, 2^261651859 is an apocalyptic number.

261651859 is a deficient number, since it is larger than the sum of its proper divisors (38284909).

261651859 is a wasteful number, since it uses less digits than its factorization.

261651859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113265.

The product of its digits is 129600, while the sum is 43.

The square root of 261651859 is about 16175.6563699901. The cubic root of 261651859 is about 639.5992437351.

The spelling of 261651859 in words is "two hundred sixty-one million, six hundred fifty-one thousand, eight hundred fifty-nine".