21928039 has 12 divisors (see below), whose sum is σ = 26618544. Its totient is φ = 17977344.

The previous prime is 21928001. The next prime is 21928043. The reversal of 21928039 is 93082912.

It is not a de Polignac number, because 21928039 - 2⁷ = 21927911 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21927995 and 21928013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928099) 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 11 ways as a sum of consecutive naturals, for example, 8602 + ... + 10855.

It is an arithmetic number, because the mean of its divisors is an integer number (2218212).

Almost surely, 2^21928039 is an apocalyptic number.

21928039 is a deficient number, since it is larger than the sum of its proper divisors (4690505).

21928039 is a wasteful number, since it uses less digits than its factorization.

21928039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19494 (or 19487 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 21928039 is about 4682.7384082393. The cubic root of 21928039 is about 279.8980879114.

The spelling of 21928039 in words is "twenty-one million, nine hundred twenty-eight thousand, thirty-nine".