20923221 has 16 divisors (see below), whose sum is σ = 30804480. Its totient is φ = 12526320.

The previous prime is 20923207. The next prime is 20923247. The reversal of 20923221 is 12232902.

It is not a de Polignac number, because 20923221 - 2⁶ = 20923157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20923121) 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, 1081 + ... + 6558.

It is an arithmetic number, because the mean of its divisors is an integer number (1925280).

Almost surely, 2^20923221 is an apocalyptic number.

It is an amenable number.

20923221 is a deficient number, since it is larger than the sum of its proper divisors (9881259).

20923221 is a wasteful number, since it uses less digits than its factorization.

20923221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7736.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 20923221 is about 4574.1907480996. The cubic root of 20923221 is about 275.5557729998. Note that the first 3 decimals are identical.

The spelling of 20923221 in words is "twenty million, nine hundred twenty-three thousand, two hundred twenty-one".