21428333 has 8 divisors (see below), whose sum is σ = 22600800. Its totient is φ = 20260368.

The previous prime is 21428327. The next prime is 21428339. The reversal of 21428333 is 33382412.

It is an interprime number because it is at equal distance from previous prime (21428327) and next prime (21428339).

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 21428333 - 2⁴ = 21428317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428339) 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, 13958 + ... + 15416.

It is an arithmetic number, because the mean of its divisors is an integer number (2825100).

Almost surely, 2^21428333 is an apocalyptic number.

It is an amenable number.

21428333 is a deficient number, since it is larger than the sum of its proper divisors (1172467).

21428333 is a wasteful number, since it uses less digits than its factorization.

21428333 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2251.

The product of its digits is 3456, while the sum is 26.

The square root of 21428333 is about 4629.0747455620. The cubic root of 21428333 is about 277.7555819717.

The spelling of 21428333 in words is "twenty-one million, four hundred twenty-eight thousand, three hundred thirty-three".