21018845 has 8 divisors (see below), whose sum is σ = 26550240. Its totient is φ = 15930000.

The previous prime is 21018841. The next prime is 21018857. The reversal of 21018845 is 54881012.

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

It is not a de Polignac number, because 21018845 - 2² = 21018841 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018841) 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, 110531 + ... + 110720.

It is an arithmetic number, because the mean of its divisors is an integer number (3318780).

Almost surely, 2^21018845 is an apocalyptic number.

It is an amenable number.

21018845 is a deficient number, since it is larger than the sum of its proper divisors (5531395).

21018845 is a wasteful number, since it uses less digits than its factorization.

21018845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221275.

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 21018845 is about 4584.6313919442. The cubic root of 21018845 is about 275.9749198312.

Adding to 21018845 its reverse (54881012), we get a palindrome (75899857).

The spelling of 21018845 in words is "twenty-one million, eighteen thousand, eight hundred forty-five".