261581190 has 64 divisors (see below), whose sum is σ = 680170176. Its totient is φ = 64000512.

The previous prime is 261581183. The next prime is 261581191. The reversal of 261581190 is 91185162.

It is a super-2 number, since 2×261581190² = 136849437923632200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261581191) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65532 + ... + 69408.

It is an arithmetic number, because the mean of its divisors is an integer number (10627659).

Almost surely, 2^261581190 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261581190, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (340085088).

261581190 is an abundant number, since it is smaller than the sum of its proper divisors (418588986).

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

261581190 is a wasteful number, since it uses less digits than its factorization.

261581190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4073.

The product of its (nonzero) digits is 4320, while the sum is 33.

The square root of 261581190 is about 16173.4717979783. The cubic root of 261581190 is about 639.5416558789.

The spelling of 261581190 in words is "two hundred sixty-one million, five hundred eighty-one thousand, one hundred ninety".