21680039 has 8 divisors (see below), whose sum is σ = 22379568. Its totient is φ = 20986560.

The previous prime is 21680027. The next prime is 21680059. The reversal of 21680039 is 93008612.

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 21680039 - 2²⁰ = 20631463 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21679993 and 21680020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680059) 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, 6419 + ... + 9195.

It is an arithmetic number, because the mean of its divisors is an integer number (2797446).

Almost surely, 2^21680039 is an apocalyptic number.

21680039 is a deficient number, since it is larger than the sum of its proper divisors (699529).

21680039 is a wasteful number, since it uses less digits than its factorization.

21680039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3025.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21680039 is about 4656.1828787108. The cubic root of 21680039 is about 278.8388950125.

The spelling of 21680039 in words is "twenty-one million, six hundred eighty thousand, thirty-nine".