261397871 has 8 divisors (see below), whose sum is σ = 303638304. Its totient is φ = 220381920.

The previous prime is 261397867. The next prime is 261397891. The reversal of 261397871 is 178793162.

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 261397871 - 2² = 261397867 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261397811) 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, 305660 + ... + 306513.

It is an arithmetic number, because the mean of its divisors is an integer number (37954788).

Almost surely, 2^261397871 is an apocalyptic number.

261397871 is a deficient number, since it is larger than the sum of its proper divisors (42240433).

261397871 is an equidigital number, since it uses as much as digits as its factorization.

261397871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612241.

The product of its digits is 127008, while the sum is 44.

The square root of 261397871 is about 16167.8035304738. The cubic root of 261397871 is about 639.3922216692.

The spelling of 261397871 in words is "two hundred sixty-one million, three hundred ninety-seven thousand, eight hundred seventy-one".