261361650 has 192 divisors, whose sum is σ = 755951616. Its totient is φ = 59136000.

The previous prime is 261361643. The next prime is 261361657. The reversal of 261361650 is 56163162.

It is an interprime number because it is at equal distance from previous prime (261361643) and next prime (261361657).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261361657) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2694402 + ... + 2694498.

It is an arithmetic number, because the mean of its divisors is an integer number (3937248).

Almost surely, 2^261361650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261361650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (377975808).

261361650 is an abundant number, since it is smaller than the sum of its proper divisors (494589966).

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

261361650 is a wasteful number, since it uses less digits than its factorization.

261361650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 261361650 is about 16166.6833333247. The cubic root of 261361650 is about 639.3626875145.

The spelling of 261361650 in words is "two hundred sixty-one million, three hundred sixty-one thousand, six hundred fifty".