261316578 has 16 divisors (see below), whose sum is σ = 525522816. Its totient is φ = 86623920.

The previous prime is 261316543. The next prime is 261316579. The reversal of 261316578 is 875613162.

It is not an unprimeable number, because it can be changed into a prime (261316579) 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, 119226 + ... + 121397.

It is an arithmetic number, because the mean of its divisors is an integer number (32845176).

Almost surely, 2^261316578 is an apocalyptic number.

261316578 is an abundant number, since it is smaller than the sum of its proper divisors (264206238).

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

261316578 is a wasteful number, since it uses less digits than its factorization.

261316578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240809.

The product of its digits is 60480, while the sum is 39.

The square root of 261316578 is about 16165.2892952771. The cubic root of 261316578 is about 639.3259325535.

It can be divided in two parts, 2613 and 16578, that added together give a palindrome (19191).

The spelling of 261316578 in words is "two hundred sixty-one million, three hundred sixteen thousand, five hundred seventy-eight".