261178906 has 24 divisors (see below), whose sum is σ = 413410176. Its totient is φ = 123623160.

The previous prime is 261178903. The next prime is 261178909. The reversal of 261178906 is 609871162.

It is an interprime number because it is at equal distance from previous prime (261178903) and next prime (261178909).

It is not an unprimeable number, because it can be changed into a prime (261178903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136005 + ... + 137911.

It is an arithmetic number, because the mean of its divisors is an integer number (17225424).

Almost surely, 2^261178906 is an apocalyptic number.

261178906 is a deficient number, since it is larger than the sum of its proper divisors (152231270).

261178906 is a wasteful number, since it uses less digits than its factorization.

261178906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2034 (or 1987 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 261178906 is about 16161.0304745706. The cubic root of 261178906 is about 639.2136386940.

The spelling of 261178906 in words is "two hundred sixty-one million, one hundred seventy-eight thousand, nine hundred six".