261305611989 has 8 divisors (see below), whose sum is σ = 348410222400. Its totient is φ = 174202371456.

The previous prime is 261305611927. The next prime is 261305611997. The reversal of 261305611989 is 989116503162.

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

It is not a de Polignac number, because 261305611989 - 2¹⁵ = 261305579221 is a prime.

It is a super-2 number, since 2×261305611989² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261305611909) 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, 248112 + ... + 764310.

It is an arithmetic number, because the mean of its divisors is an integer number (43551277800).

Almost surely, 2^261305611989 is an apocalyptic number.

It is an amenable number.

261305611989 is a deficient number, since it is larger than the sum of its proper divisors (87104610411).

261305611989 is a wasteful number, since it uses less digits than its factorization.

261305611989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684939.

The product of its (nonzero) digits is 699840, while the sum is 51.

The spelling of 261305611989 in words is "two hundred sixty-one billion, three hundred five million, six hundred eleven thousand, nine hundred eighty-nine".