21428673 has 8 divisors (see below), whose sum is σ = 32653248. Its totient is φ = 12244944.

The previous prime is 21428621. The next prime is 21428681. The reversal of 21428673 is 37682412.

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

It is not a de Polignac number, because 21428673 - 2¹² = 21424577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21428683) 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 7 ways as a sum of consecutive naturals, for example, 510186 + ... + 510227.

It is an arithmetic number, because the mean of its divisors is an integer number (4081656).

Almost surely, 2^21428673 is an apocalyptic number.

It is an amenable number.

21428673 is a deficient number, since it is larger than the sum of its proper divisors (11224575).

21428673 is a wasteful number, since it uses less digits than its factorization.

21428673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1020423.

The product of its digits is 16128, while the sum is 33.

The square root of 21428673 is about 4629.1114698179. Note that the first 3 decimals coincide. The cubic root of 21428673 is about 277.7570509987.

The spelling of 21428673 in words is "twenty-one million, four hundred twenty-eight thousand, six hundred seventy-three".