21821426 has 8 divisors (see below), whose sum is σ = 35707824. Its totient is φ = 9918820.

The previous prime is 21821419. The next prime is 21821441. The reversal of 21821426 is 62412812.

It is a happy number.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21821395 and 21821404.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 495920 + ... + 495963.

It is an arithmetic number, because the mean of its divisors is an integer number (4463478).

Almost surely, 2^21821426 is an apocalyptic number.

21821426 is a deficient number, since it is larger than the sum of its proper divisors (13886398).

21821426 is a wasteful number, since it uses less digits than its factorization.

21821426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991896.

The product of its digits is 1536, while the sum is 26.

The square root of 21821426 is about 4671.3409209776. The cubic root of 21821426 is about 279.4437340536.

The spelling of 21821426 in words is "twenty-one million, eight hundred twenty-one thousand, four hundred twenty-six".