21085441 has 8 divisors (see below), whose sum is σ = 22817984. Its totient is φ = 19368720.

The previous prime is 21085409. The next prime is 21085453. The reversal of 21085441 is 14458012.

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

It is a cyclic number.

It is not a de Polignac number, because 21085441 - 2⁵ = 21085409 is a prime.

It is a super-4 number, since 4×21085441⁴ (a number of 30 digits) contains 4444 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21085241) 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, 1101 + ... + 6586.

It is an arithmetic number, because the mean of its divisors is an integer number (2852248).

Almost surely, 2^21085441 is an apocalyptic number.

It is an amenable number.

21085441 is a deficient number, since it is larger than the sum of its proper divisors (1732543).

21085441 is a wasteful number, since it uses less digits than its factorization.

21085441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7911.

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 21085441 is about 4591.8886092761. Note that the first 3 decimals coincide. The cubic root of 21085441 is about 276.2660783828.

The spelling of 21085441 in words is "twenty-one million, eighty-five thousand, four hundred forty-one".