261478878 has 8 divisors (see below), whose sum is σ = 522957768. Its totient is φ = 87159624.

The previous prime is 261478849. The next prime is 261478897. The reversal of 261478878 is 878874162.

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

261478878 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 261478878.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21789901 + ... + 21789912.

It is an arithmetic number, because the mean of its divisors is an integer number (65369721).

Almost surely, 2^261478878 is an apocalyptic number.

261478878 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

261478878 is a wasteful number, since it uses less digits than its factorization.

261478878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43579818.

The product of its digits is 1204224, while the sum is 51.

The square root of 261478878 is about 16170.3085313794. The cubic root of 261478878 is about 639.4582639007.

The spelling of 261478878 in words is "two hundred sixty-one million, four hundred seventy-eight thousand, eight hundred seventy-eight".