261329538 has 32 divisors (see below), whose sum is σ = 534957696. Its totient is φ = 85075328.

The previous prime is 261329507. The next prime is 261329539. The reversal of 261329538 is 835923162.

It is a junction number, because it is equal to n+sod(n) for n = 261329496 and 261329505.

It is not an unprimeable number, because it can be changed into a prime (261329539) 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 15 ways as a sum of consecutive naturals, for example, 72331 + ... + 75857.

It is an arithmetic number, because the mean of its divisors is an integer number (16717428).

Almost surely, 2^261329538 is an apocalyptic number.

261329538 is an abundant number, since it is smaller than the sum of its proper divisors (273628158).

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

261329538 is a wasteful number, since it uses less digits than its factorization.

261329538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3818.

The product of its digits is 77760, while the sum is 39.

The square root of 261329538 is about 16165.6901492018. The cubic root of 261329538 is about 639.3365015055.

The spelling of 261329538 in words is "two hundred sixty-one million, three hundred twenty-nine thousand, five hundred thirty-eight".