215331261 has 4 divisors (see below), whose sum is σ = 287108352. Its totient is φ = 143554172.

The previous prime is 215331241. The next prime is 215331269. The reversal of 215331261 is 162133512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 215331261 - 2⁹ = 215330749 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215331269) 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 3 ways as a sum of consecutive naturals, for example, 35888541 + ... + 35888546.

It is an arithmetic number, because the mean of its divisors is an integer number (71777088).

Almost surely, 2^215331261 is an apocalyptic number.

It is an amenable number.

215331261 is a deficient number, since it is larger than the sum of its proper divisors (71777091).

215331261 is an equidigital number, since it uses as much as digits as its factorization.

215331261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71777090.

The product of its digits is 1080, while the sum is 24.

The square root of 215331261 is about 14674.1698572696. The cubic root of 215331261 is about 599.3801571007.

Adding to 215331261 its reverse (162133512), we get a palindrome (377464773).

The spelling of 215331261 in words is "two hundred fifteen million, three hundred thirty-one thousand, two hundred sixty-one".