21712285 has 8 divisors (see below), whose sum is σ = 29776896. Its totient is φ = 14888400.

The previous prime is 21712283. The next prime is 21712289. The reversal of 21712285 is 58221712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21712285 - 2¹ = 21712283 is a prime.

It is a super-3 number, since 3×21712285³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 310141 + ... + 310210.

It is an arithmetic number, because the mean of its divisors is an integer number (3722112).

Almost surely, 2^21712285 is an apocalyptic number.

It is an amenable number.

21712285 is a deficient number, since it is larger than the sum of its proper divisors (8064611).

21712285 is an equidigital number, since it uses as much as digits as its factorization.

21712285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620363.

The product of its digits is 2240, while the sum is 28.

The square root of 21712285 is about 4659.6442997293. The cubic root of 21712285 is about 278.9770710378.

Adding to 21712285 its reverse (58221712), we get a palindrome (79933997).

The spelling of 21712285 in words is "twenty-one million, seven hundred twelve thousand, two hundred eighty-five".