261971478 has 24 divisors (see below), whose sum is σ = 570892608. Its totient is φ = 86818032.

The previous prime is 261971447. The next prime is 261971491. The reversal of 261971478 is 874179162.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 38950 + ... + 45177.

It is an arithmetic number, because the mean of its divisors is an integer number (23787192).

Almost surely, 2^261971478 is an apocalyptic number.

261971478 is an abundant number, since it is smaller than the sum of its proper divisors (308921130).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261971478 is a wasteful number, since it uses less digits than its factorization.

261971478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84308 (or 84305 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 261971478 is about 16185.5329847367. The cubic root of 261971478 is about 639.8595704260.

The spelling of 261971478 in words is "two hundred sixty-one million, nine hundred seventy-one thousand, four hundred seventy-eight".