21234085 has 4 divisors (see below), whose sum is σ = 25480908. Its totient is φ = 16987264.

The previous prime is 21234067. The next prime is 21234091. The reversal of 21234085 is 58043212.

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 5377761 + 15856324 = 2319^2 + 3982^2 .

It is a cyclic number.

It is not a de Polignac number, because 21234085 - 2⁷ = 21233957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2123404 + ... + 2123413.

It is an arithmetic number, because the mean of its divisors is an integer number (6370227).

Almost surely, 2^21234085 is an apocalyptic number.

It is an amenable number.

21234085 is a deficient number, since it is larger than the sum of its proper divisors (4246823).

21234085 is an equidigital number, since it uses as much as digits as its factorization.

21234085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4246822.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 21234085 is about 4608.0456811972. The cubic root of 21234085 is about 276.9137475984.

Adding to 21234085 its reverse (58043212), we get a palindrome (79277297).

The spelling of 21234085 in words is "twenty-one million, two hundred thirty-four thousand, eighty-five".