20766221 has 16 divisors (see below), whose sum is σ = 25142400. Its totient is φ = 16754688.

The previous prime is 20766211. The next prime is 20766241. The reversal of 20766221 is 12266702.

It is a cyclic number.

It is not a de Polignac number, because 20766221 - 2¹⁴ = 20749837 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 (20766211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25265 + ... + 26073.

It is an arithmetic number, because the mean of its divisors is an integer number (1571400).

Almost surely, 2^20766221 is an apocalyptic number.

It is an amenable number.

20766221 is a deficient number, since it is larger than the sum of its proper divisors (4376179).

20766221 is a wasteful number, since it uses less digits than its factorization.

20766221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1028.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 20766221 is about 4556.9969278023. The cubic root of 20766221 is about 274.8648195112.

The spelling of 20766221 in words is "twenty million, seven hundred sixty-six thousand, two hundred twenty-one".