261171778 has 16 divisors (see below), whose sum is σ = 450201024. Its totient is φ = 111311280.

The previous prime is 261171773. The next prime is 261171793. The reversal of 261171778 is 877171162.

It is a self number, because there is not a number n which added to its sum of digits gives 261171778.

It is not an unprimeable number, because it can be changed into a prime (261171773) 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, 49000 + ... + 54067.

It is an arithmetic number, because the mean of its divisors is an integer number (28137564).

Almost surely, 2^261171778 is an apocalyptic number.

261171778 is a deficient number, since it is larger than the sum of its proper divisors (189029246).

261171778 is a wasteful number, since it uses less digits than its factorization.

261171778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103257.

The product of its digits is 32928, while the sum is 40.

The square root of 261171778 is about 16160.8099425740. The cubic root of 261171778 is about 639.2078235788.

The spelling of 261171778 in words is "two hundred sixty-one million, one hundred seventy-one thousand, seven hundred seventy-eight".