261499590 has 128 divisors (see below), whose sum is σ = 770826240. Its totient is φ = 63335520.

The previous prime is 261499577. The next prime is 261499591. The reversal of 261499590 is 95994162.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261499591) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 240027 + ... + 241113.

It is an arithmetic number, because the mean of its divisors is an integer number (6022080).

Almost surely, 2^261499590 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261499590, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (385413120).

261499590 is an abundant number, since it is smaller than the sum of its proper divisors (509326650).

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

261499590 is a wasteful number, since it uses less digits than its factorization.

261499590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1126 (or 1108 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 45.

The square root of 261499590 is about 16170.9489517468. The cubic root of 261499590 is about 639.4751474950.

The spelling of 261499590 in words is "two hundred sixty-one million, four hundred ninety-nine thousand, five hundred ninety".