261855012 has 24 divisors (see below), whose sum is σ = 646936416. Its totient is φ = 82150528.

The previous prime is 261854969. The next prime is 261855019. The reversal of 261855012 is 210558162.

261855012 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (261855019) 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, 641598 + ... + 642005.

It is an arithmetic number, because the mean of its divisors is an integer number (26955684).

Almost surely, 2^261855012 is an apocalyptic number.

It is an amenable number.

261855012 is an abundant number, since it is smaller than the sum of its proper divisors (385081404).

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

261855012 is a wasteful number, since it uses less digits than its factorization.

261855012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1283627 (or 1283625 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 261855012 is about 16181.9347421747. The cubic root of 261855012 is about 639.7647344900.

It can be divided in two parts, 2618 and 55012, that added together give a triangular number (57630 = T₃₃₉).

The spelling of 261855012 in words is "two hundred sixty-one million, eight hundred fifty-five thousand, twelve".