21380085 has 16 divisors (see below), whose sum is σ = 38009280. Its totient is φ = 11402640.

The previous prime is 21380081. The next prime is 21380113. The reversal of 21380085 is 58008312.

It is a happy number.

It is not a de Polignac number, because 21380085 - 2² = 21380081 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21380081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79051 + ... + 79320.

It is an arithmetic number, because the mean of its divisors is an integer number (2375580).

Almost surely, 2^21380085 is an apocalyptic number.

It is an amenable number.

21380085 is a deficient number, since it is larger than the sum of its proper divisors (16629195).

21380085 is a wasteful number, since it uses less digits than its factorization.

21380085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158385 (or 158379 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 21380085 is about 4623.8604001419. The cubic root of 21380085 is about 277.5469606427.

Adding to 21380085 its reverse (58008312), we get a palindrome (79388397).

The spelling of 21380085 in words is "twenty-one million, three hundred eighty thousand, eighty-five".