261778983 has 8 divisors (see below), whose sum is σ = 354248448. Its totient is φ = 171914424.

The previous prime is 261778943. The next prime is 261778987. The reversal of 261778983 is 389877162.

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

It is not a de Polignac number, because 261778983 - 2¹⁰ = 261777959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261778987) 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, 650991 + ... + 651392.

It is an arithmetic number, because the mean of its divisors is an integer number (44281056).

Almost surely, 2^261778983 is an apocalyptic number.

261778983 is a deficient number, since it is larger than the sum of its proper divisors (92469465).

261778983 is a wasteful number, since it uses less digits than its factorization.

261778983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1302453.

The product of its digits is 1016064, while the sum is 51.

The square root of 261778983 is about 16179.5853778767. The cubic root of 261778983 is about 639.7028104237.

The spelling of 261778983 in words is "two hundred sixty-one million, seven hundred seventy-eight thousand, nine hundred eighty-three".