261659553120 has 1536 divisors, whose sum is σ = 1127831040000. Its totient is φ = 56574443520.

The previous prime is 261659553059. The next prime is 261659553121. The reversal of 261659553120 is 21355956162.

261659553120 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 5 + 95 + 531 + 20 = 666.

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 (261659553121) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 3584377404 + ... + 3584377476.

It is an arithmetic number, because the mean of its divisors is an integer number (734265000).

Almost surely, 2^261659553120 is an apocalyptic number.

261659553120 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 261659553120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (563915520000).

261659553120 is an abundant number, since it is smaller than the sum of its proper divisors (866171486880).

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

261659553120 is a wasteful number, since it uses less digits than its factorization.

261659553120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 486000, while the sum is 45.

The spelling of 261659553120 in words is "two hundred sixty-one billion, six hundred fifty-nine million, five hundred fifty-three thousand, one hundred twenty".