261216030 has 64 divisors (see below), whose sum is σ = 640584000. Its totient is φ = 68152320.

The previous prime is 261216019. The next prime is 261216031. The reversal of 261216030 is 30612162.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 261215988 and 261216006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261216031) 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 31 ways as a sum of consecutive naturals, for example, 638466 + ... + 638874.

It is an arithmetic number, because the mean of its divisors is an integer number (10009125).

Almost surely, 2^261216030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261216030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320292000).

261216030 is an abundant number, since it is smaller than the sum of its proper divisors (379367970).

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

261216030 is a wasteful number, since it uses less digits than its factorization.

261216030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 261216030 is about 16162.1789991325. The cubic root of 261216030 is about 639.2439232261.

Adding to 261216030 its reverse (30612162), we get a palindrome (291828192).

The spelling of 261216030 in words is "two hundred sixty-one million, two hundred sixteen thousand, thirty".