215055261 has 12 divisors (see below), whose sum is σ = 311699388. Its totient is φ = 142879104.

The previous prime is 215055251. The next prime is 215055263. The reversal of 215055261 is 162550512.

215055261 is a `hidden beast` number, since 2 + 1 + 50 + 552 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 178222500 + 36832761 = 13350^2 + 6069^2 .

It is not a de Polignac number, because 215055261 - 2¹⁰ = 215054237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215055263) 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 11 ways as a sum of consecutive naturals, for example, 38140 + ... + 43413.

It is an arithmetic number, because the mean of its divisors is an integer number (25974949).

Almost surely, 2^215055261 is an apocalyptic number.

It is an amenable number.

215055261 is a deficient number, since it is larger than the sum of its proper divisors (96644127).

215055261 is a wasteful number, since it uses less digits than its factorization.

215055261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81852 (or 81849 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 215055261 is about 14664.7625620056. The cubic root of 215055261 is about 599.1239632218.

The spelling of 215055261 in words is "two hundred fifteen million, fifty-five thousand, two hundred sixty-one".