261661016 has 16 divisors (see below), whose sum is σ = 502581240. Its totient is φ = 127639360.

The previous prime is 261660983. The next prime is 261661019. The reversal of 261661016 is 610166162.

It is a self number, because there is not a number n which added to its sum of digits gives 261661016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261661019) 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 3 ways as a sum of consecutive naturals, for example, 398546 + ... + 399201.

Almost surely, 2^261661016 is an apocalyptic number.

It is an amenable number.

261661016 is a deficient number, since it is larger than the sum of its proper divisors (240920224).

261661016 is a wasteful number, since it uses less digits than its factorization.

261661016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797794 (or 797790 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 261661016 is about 16175.9394163059. The cubic root of 261661016 is about 639.6067049751.

The spelling of 261661016 in words is "two hundred sixty-one million, six hundred sixty-one thousand, sixteen".