261553600 has 252 divisors, whose sum is σ = 812659792. Its totient is φ = 81100800.

The previous prime is 261553597. The next prime is 261553609. The reversal of 261553600 is 6355162.

It is a super-3 number, since 3×261553600³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261553609) 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 35 ways as a sum of consecutive naturals, for example, 1355104 + ... + 1355296.

Almost surely, 2^261553600 is an apocalyptic number.

261553600 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 261553600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (406329896).

261553600 is an abundant number, since it is smaller than the sum of its proper divisors (551106192).

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

261553600 is a wasteful number, since it uses less digits than its factorization.

261553600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 218 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 261553600 is about 16172.6188355504. The cubic root of 261553600 is about 639.5191700945.

The spelling of 261553600 in words is "two hundred sixty-one million, five hundred fifty-three thousand, six hundred".