261556170 has 16 divisors (see below), whose sum is σ = 627734880. Its totient is φ = 69748304.

The previous prime is 261556151. The next prime is 261556171. The reversal of 261556170 is 71655162.

It is not an unprimeable number, because it can be changed into a prime (261556171) 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, 4359240 + ... + 4359299.

It is an arithmetic number, because the mean of its divisors is an integer number (39233430).

Almost surely, 2^261556170 is an apocalyptic number.

261556170 is an abundant number, since it is smaller than the sum of its proper divisors (366178710).

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

261556170 is a wasteful number, since it uses less digits than its factorization.

261556170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8718549.

The product of its (nonzero) digits is 12600, while the sum is 33.

The square root of 261556170 is about 16172.6982906378. The cubic root of 261556170 is about 639.5212647052.

It can be divided in two parts, 261556 and 170, that added together give a triangular number (261726 = T₇₂₃).

The spelling of 261556170 in words is "two hundred sixty-one million, five hundred fifty-six thousand, one hundred seventy".