20806621 has 8 divisors (see below), whose sum is σ = 23018688. Its totient is φ = 18648000.

The previous prime is 20806619. The next prime is 20806631. The reversal of 20806621 is 12660802.

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 20806621 - 2¹ = 20806619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806631) 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, 12540 + ... + 14101.

It is an arithmetic number, because the mean of its divisors is an integer number (2877336).

Almost surely, 2^20806621 is an apocalyptic number.

It is an amenable number.

20806621 is a deficient number, since it is larger than the sum of its proper divisors (2212067).

20806621 is a wasteful number, since it uses less digits than its factorization.

20806621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26723.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 20806621 is about 4561.4275177843. The cubic root of 20806621 is about 275.0429508671.

The spelling of 20806621 in words is "twenty million, eight hundred six thousand, six hundred twenty-one".