20606921 has 2 divisors, whose sum is σ = 20606922. Its totient is φ = 20606920.

The previous prime is 20606917. The next prime is 20606939. The reversal of 20606921 is 12960602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14899600 + 5707321 = 3860^2 + 2389^2 .

It is a cyclic number.

It is not a de Polignac number, because 20606921 - 2² = 20606917 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20506921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10303460 + 10303461.

It is an arithmetic number, because the mean of its divisors is an integer number (10303461).

Almost surely, 2^20606921 is an apocalyptic number.

It is an amenable number.

20606921 is a deficient number, since it is larger than the sum of its proper divisors (1).

20606921 is an equidigital number, since it uses as much as digits as its factorization.

20606921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 20606921 is about 4539.4846623818. The cubic root of 20606921 is about 274.1601750520.

The spelling of 20606921 in words is "twenty million, six hundred six thousand, nine hundred twenty-one".