20706021 has 12 divisors (see below), whose sum is σ = 34181472. Its totient is φ = 11831976.

The previous prime is 20706019. The next prime is 20706031. The reversal of 20706021 is 12060702.

It is a happy number.

It is not a de Polignac number, because 20706021 - 2¹ = 20706019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20705985 and 20706003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20706031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164271 + ... + 164396.

It is an arithmetic number, because the mean of its divisors is an integer number (2848456).

Almost surely, 2^20706021 is an apocalyptic number.

20706021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20706021 is a deficient number, since it is larger than the sum of its proper divisors (13475451).

20706021 is a wasteful number, since it uses less digits than its factorization.

20706021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328680 (or 328677 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20706021 is about 4550.3869066267. The cubic root of 20706021 is about 274.5989570259.

Adding to 20706021 its reverse (12060702), we get a palindrome (32766723).

The spelling of 20706021 in words is "twenty million, seven hundred six thousand, twenty-one".