261190315520 has 80 divisors (see below), whose sum is σ = 627045165648. Its totient is φ = 104342568960.

The previous prime is 261190315501. The next prime is 261190315523. The reversal of 261190315520 is 25513091162.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261190315523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1949900 + ... + 2079540.

Almost surely, 2^261190315520 is an apocalyptic number.

261190315520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261190315520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313522582824).

261190315520 is an abundant number, since it is smaller than the sum of its proper divisors (365854850128).

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

261190315520 is an equidigital number, since it uses as much as digits as its factorization.

261190315520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130451 (or 130435 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 35.

The spelling of 261190315520 in words is "two hundred sixty-one billion, one hundred ninety million, three hundred fifteen thousand, five hundred twenty".