21032217 has 10 divisors (see below), whose sum is σ = 31418618. Its totient is φ = 14021424.

The previous prime is 21032201. The next prime is 21032237. The reversal of 21032217 is 71223012.

It can be written as a sum of positive squares in only one way, i.e., 20985561 + 46656 = 4581^2 + 216^2 .

It is not a de Polignac number, because 21032217 - 2⁴ = 21032201 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21032217.

It is not an unprimeable number, because it can be changed into a prime (21032237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 129748 + ... + 129909.

Almost surely, 2^21032217 is an apocalyptic number.

21032217 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21032217 is a deficient number, since it is larger than the sum of its proper divisors (10386401).

21032217 is an equidigital number, since it uses as much as digits as its factorization.

21032217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259669 (or 259660 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21032217 is about 4586.0895106834. The cubic root of 21032217 is about 276.0334316781.

Adding to 21032217 its reverse (71223012), we get a palindrome (92255229).

The spelling of 21032217 in words is "twenty-one million, thirty-two thousand, two hundred seventeen".