261853617 has 8 divisors (see below), whose sum is σ = 357257824. Its totient is φ = 170509248.

The previous prime is 261853589. The next prime is 261853633. The reversal of 261853617 is 716358162.

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

It is not a de Polignac number, because 261853617 - 2¹⁵ = 261820849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261853667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1014808 + ... + 1015065.

It is an arithmetic number, because the mean of its divisors is an integer number (44657228).

Almost surely, 2^261853617 is an apocalyptic number.

It is an amenable number.

261853617 is a deficient number, since it is larger than the sum of its proper divisors (95404207).

261853617 is a wasteful number, since it uses less digits than its factorization.

261853617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2029919.

The product of its digits is 60480, while the sum is 39.

The square root of 261853617 is about 16181.8916384952. The cubic root of 261853617 is about 639.7635983990.

The spelling of 261853617 in words is "two hundred sixty-one million, eight hundred fifty-three thousand, six hundred seventeen".