261873216 has 224 divisors, whose sum is σ = 877824000. Its totient is φ = 75778560.

The previous prime is 261873187. The next prime is 261873221. The reversal of 261873216 is 612378162.

261873216 is a `hidden beast` number, since 2 + 618 + 7 + 32 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 436885 + ... + 437483.

Almost surely, 2^261873216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261873216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (438912000).

261873216 is an abundant number, since it is smaller than the sum of its proper divisors (615950784).

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

261873216 is a wasteful number, since it uses less digits than its factorization.

261873216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 654 (or 638 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 261873216 is about 16182.4972114937. The cubic root of 261873216 is about 639.7795594972.

It can be divided in two parts, 26187 and 3216, that added together give a triangular number (29403 = T₂₄₂).

The spelling of 261873216 in words is "two hundred sixty-one million, eight hundred seventy-three thousand, two hundred sixteen".