261288078 has 8 divisors (see below), whose sum is σ = 522576168. Its totient is φ = 87096024.

The previous prime is 261288077. The next prime is 261288089. The reversal of 261288078 is 870882162.

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

261288078 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261288077) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21774001 + ... + 21774012.

It is an arithmetic number, because the mean of its divisors is an integer number (65322021).

Almost surely, 2^261288078 is an apocalyptic number.

261288078 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.

261288078 is a wasteful number, since it uses less digits than its factorization.

261288078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43548018.

The product of its (nonzero) digits is 86016, while the sum is 42.

The square root of 261288078 is about 16164.4077528377. The cubic root of 261288078 is about 639.3026894160.

The spelling of 261288078 in words is "two hundred sixty-one million, two hundred eighty-eight thousand, seventy-eight".