21214621 has 8 divisors (see below), whose sum is σ = 22410080. Its totient is φ = 20027088.

The previous prime is 21214619. The next prime is 21214643. The reversal of 21214621 is 12641212.

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 21214621 - 2¹ = 21214619 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21214651) 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, 4015 + ... + 7651.

It is an arithmetic number, because the mean of its divisors is an integer number (2801260).

Almost surely, 2^21214621 is an apocalyptic number.

It is an amenable number.

21214621 is a deficient number, since it is larger than the sum of its proper divisors (1195459).

21214621 is a wasteful number, since it uses less digits than its factorization.

21214621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3963.

The product of its digits is 192, while the sum is 19.

The square root of 21214621 is about 4605.9332387693. The cubic root of 21214621 is about 276.8291117112.

Adding to 21214621 its reverse (12641212), we get a palindrome (33855833).

It can be divided in two parts, 2 and 1214621, that multiplied together give a palindrome (2429242).

The spelling of 21214621 in words is "twenty-one million, two hundred fourteen thousand, six hundred twenty-one".