215232021 has 6 divisors (see below), whose sum is σ = 310890710. Its totient is φ = 143488008.

The previous prime is 215232013. The next prime is 215232029. The reversal of 215232021 is 120232512.

It is an interprime number because it is at equal distance from previous prime (215232013) and next prime (215232029).

It can be written as a sum of positive squares in only one way, i.e., 212751396 + 2480625 = 14586^2 + 1575^2 .

It is not a de Polignac number, because 215232021 - 2³ = 215232013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 215231985 and 215232003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215232029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11957326 + ... + 11957343.

Almost surely, 2^215232021 is an apocalyptic number.

It is an amenable number.

215232021 is a deficient number, since it is larger than the sum of its proper divisors (95658689).

215232021 is a wasteful number, since it uses less digits than its factorization.

215232021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23914675 (or 23914672 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 215232021 is about 14670.7880156452. The cubic root of 215232021 is about 599.2880639125.

Adding to 215232021 its reverse (120232512), we get a palindrome (335464533).

The spelling of 215232021 in words is "two hundred fifteen million, two hundred thirty-two thousand, twenty-one".