261216400 has 60 divisors (see below), whose sum is σ = 642209392. Its totient is φ = 102049920.

The previous prime is 261216353. The next prime is 261216409. The reversal of 261216400 is 4612162.

It is not an unprimeable number, because it can be changed into a prime (261216409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9607 + ... + 24793.

Almost surely, 2^261216400 is an apocalyptic number.

261216400 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 261216400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (321104696).

261216400 is an abundant number, since it is smaller than the sum of its proper divisors (380992992).

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

261216400 is a wasteful number, since it uses less digits than its factorization.

261216400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15248 (or 15237 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 261216400 is about 16162.1904456048. The cubic root of 261216400 is about 639.2442250454.

Adding to 261216400 its reverse (4612162), we get a palindrome (265828562).

The spelling of 261216400 in words is "two hundred sixty-one million, two hundred sixteen thousand, four hundred".