20211668 has 18 divisors (see below), whose sum is σ = 37332666. Its totient is φ = 9573264.

The previous prime is 20211661. The next prime is 20211671. The reversal of 20211668 is 86611202.

It can be written as a sum of positive squares in only one way, i.e., 17156164 + 3055504 = 4142^2 + 1748^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5555 + ... + 8442.

It is an arithmetic number, because the mean of its divisors is an integer number (2074037).

Almost surely, 2^20211668 is an apocalyptic number.

It is an amenable number.

20211668 is a deficient number, since it is larger than the sum of its proper divisors (17120998).

20211668 is a wasteful number, since it uses less digits than its factorization.

20211668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14039 (or 14018 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 20211668 is about 4495.7388714204. The cubic root of 20211668 is about 272.3959954359.

The spelling of 20211668 in words is "twenty million, two hundred eleven thousand, six hundred sixty-eight".