20606021 has 4 divisors (see below), whose sum is σ = 20632992. Its totient is φ = 20579052.

The previous prime is 20606017. The next prime is 20606063. The reversal of 20606021 is 12060602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20606021 - 2² = 20606017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20606921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12305 + ... + 13878.

It is an arithmetic number, because the mean of its divisors is an integer number (5158248).

Almost surely, 2^20606021 is an apocalyptic number.

It is an amenable number.

20606021 is a deficient number, since it is larger than the sum of its proper divisors (26971).

20606021 is an equidigital number, since it uses as much as digits as its factorization.

20606021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26970.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 20606021 is about 4539.3855311044. The cubic root of 20606021 is about 274.1561837110.

Adding to 20606021 its reverse (12060602), we get a palindrome (32666623).

The spelling of 20606021 in words is "twenty million, six hundred six thousand, twenty-one".