21428433 has 24 divisors (see below), whose sum is σ = 34786752. Its totient is φ = 12611808.

The previous prime is 21428431. The next prime is 21428453. The reversal of 21428433 is 33482412.

It is not a de Polignac number, because 21428433 - 2¹ = 21428431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21428397 and 21428406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21428431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1291 + ... + 6672.

It is an arithmetic number, because the mean of its divisors is an integer number (1449448).

Almost surely, 2^21428433 is an apocalyptic number.

21428433 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21428433 is a deficient number, since it is larger than the sum of its proper divisors (13358319).

21428433 is a wasteful number, since it uses less digits than its factorization.

21428433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8005 (or 8002 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 21428433 is about 4629.0855468440. The cubic root of 21428433 is about 277.7560140401.

The spelling of 21428433 in words is "twenty-one million, four hundred twenty-eight thousand, four hundred thirty-three".