21420833 has 8 divisors (see below), whose sum is σ = 25921152. Its totient is φ = 17280576.

The previous prime is 21420827. The next prime is 21420859. The reversal of 21420833 is 33802412.

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 21420833 - 2¹² = 21416737 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21420799 and 21420808.

It is not an unprimeable number, because it can be changed into a prime (21420863) 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, 89885 + ... + 90122.

It is an arithmetic number, because the mean of its divisors is an integer number (3240144).

Almost surely, 2^21420833 is an apocalyptic number.

It is an amenable number.

21420833 is a deficient number, since it is larger than the sum of its proper divisors (4500319).

21420833 is a wasteful number, since it uses less digits than its factorization.

21420833 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180031.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 21420833 is about 4628.2645775712. The cubic root of 21420833 is about 277.7231730118.

The spelling of 21420833 in words is "twenty-one million, four hundred twenty thousand, eight hundred thirty-three".