215730261 has 6 divisors (see below), whose sum is σ = 311610390. Its totient is φ = 143820168.

The previous prime is 215730259. The next prime is 215730283. The reversal of 215730261 is 162037512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 214066161 + 1664100 = 14631^2 + 1290^2 .

It is not a de Polignac number, because 215730261 - 2¹ = 215730259 is a prime.

It is a super-2 number, since 2×215730261² = 93079091022256242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215730241) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11985006 + ... + 11985023.

It is an arithmetic number, because the mean of its divisors is an integer number (51935065).

Almost surely, 2^215730261 is an apocalyptic number.

It is an amenable number.

215730261 is a deficient number, since it is larger than the sum of its proper divisors (95880129).

215730261 is a wasteful number, since it uses less digits than its factorization.

215730261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23970035 (or 23970032 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 215730261 is about 14687.7588828248. The cubic root of 215730261 is about 599.7501376291.

Adding to 215730261 its reverse (162037512), we get a palindrome (377767773).

The spelling of 215730261 in words is "two hundred fifteen million, seven hundred thirty thousand, two hundred sixty-one".