261004138 has 16 divisors (see below), whose sum is σ = 411656256. Its totient is φ = 123872320.

The previous prime is 261004103. The next prime is 261004151. The reversal of 261004138 is 831400162.

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 7 ways as a sum of consecutive naturals, for example, 15631 + ... + 27682.

It is an arithmetic number, because the mean of its divisors is an integer number (25728516).

Almost surely, 2^261004138 is an apocalyptic number.

261004138 is a deficient number, since it is larger than the sum of its proper divisors (150652118).

261004138 is a wasteful number, since it uses less digits than its factorization.

261004138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43469.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 261004138 is about 16155.6224887808. The cubic root of 261004138 is about 639.0710301681.

The spelling of 261004138 in words is "two hundred sixty-one million, four thousand, one hundred thirty-eight".