21226421 has 8 divisors (see below), whose sum is σ = 22529664. Its totient is φ = 19929280.

The previous prime is 21226417. The next prime is 21226423. The reversal of 21226421 is 12462212.

It is a happy number.

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 21226421 - 2² = 21226417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21226393 and 21226402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226423) 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, 7076 + ... + 9618.

It is an arithmetic number, because the mean of its divisors is an integer number (2816208).

Almost surely, 2^21226421 is an apocalyptic number.

It is an amenable number.

21226421 is a deficient number, since it is larger than the sum of its proper divisors (1303243).

21226421 is a wasteful number, since it uses less digits than its factorization.

21226421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3051.

The product of its digits is 384, while the sum is 20.

The square root of 21226421 is about 4607.2140171692. The cubic root of 21226421 is about 276.8804281760.

Adding to 21226421 its reverse (12462212), we get a palindrome (33688633).

It can be divided in two parts, 212264 and 21, that multiplied together give a palindrome (4457544).

The spelling of 21226421 in words is "twenty-one million, two hundred twenty-six thousand, four hundred twenty-one".