261824400 has 150 divisors (see below), whose sum is σ = 939783042. Its totient is φ = 69811200.

The previous prime is 261824371. The next prime is 261824411. The reversal of 261824400 is 4428162.

261824400 is a `hidden beast` number, since 2 + 618 + 2 + 4 + 40 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 7485696 + 254338704 = 2736^2 + 15948^2 .

It is a tau number, because it is divible by the number of its divisors (150).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 28360 + ... + 36440.

Almost surely, 2^261824400 is an apocalyptic number.

261824400 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 261824400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (469891521).

261824400 is an abundant number, since it is smaller than the sum of its proper divisors (677958642).

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

261824400 is a wasteful number, since it uses less digits than its factorization.

261824400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8111 (or 8091 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 261824400 is about 16180.9888449378. The cubic root of 261824400 is about 639.7398030834.

The spelling of 261824400 in words is "two hundred sixty-one million, eight hundred twenty-four thousand, four hundred".