261866650 has 12 divisors (see below), whose sum is σ = 487072062. Its totient is φ = 104746640.

The previous prime is 261866617. The next prime is 261866651. The reversal of 261866650 is 56668162.

261866650 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 195916009 + 65950641 = 13997^2 + 8121^2 .

It is not an unprimeable number, because it can be changed into a prime (261866651) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2618617 + ... + 2618716.

Almost surely, 2^261866650 is an apocalyptic number.

261866650 is a deficient number, since it is larger than the sum of its proper divisors (225205412).

261866650 is a wasteful number, since it uses less digits than its factorization.

261866650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5237345 (or 5237340 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 261866650 is about 16182.2943367126. The cubic root of 261866650 is about 639.7742123452.

The spelling of 261866650 in words is "two hundred sixty-one million, eight hundred sixty-six thousand, six hundred fifty".