215332661 has 4 divisors (see below), whose sum is σ = 217308300. Its totient is φ = 213357024.

The previous prime is 215332657. The next prime is 215332703. The reversal of 215332661 is 166233512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 61324561 + 154008100 = 7831^2 + 12410^2 .

It is a cyclic number.

It is not a de Polignac number, because 215332661 - 2² = 215332657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215332631) 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, 987656 + ... + 987873.

It is an arithmetic number, because the mean of its divisors is an integer number (54327075).

Almost surely, 2^215332661 is an apocalyptic number.

It is an amenable number.

215332661 is a deficient number, since it is larger than the sum of its proper divisors (1975639).

215332661 is a wasteful number, since it uses less digits than its factorization.

215332661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1975638.

The product of its digits is 6480, while the sum is 29.

The square root of 215332661 is about 14674.2175600609. The cubic root of 215332661 is about 599.3814560767.

The spelling of 215332661 in words is "two hundred fifteen million, three hundred thirty-two thousand, six hundred sixty-one".