20923643 has 4 divisors (see below), whose sum is σ = 22533168. Its totient is φ = 19314120.

The previous prime is 20923621. The next prime is 20923649. The reversal of 20923643 is 34632902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20923643 - 2¹⁰ = 20922619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20923649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 804743 + ... + 804768.

It is an arithmetic number, because the mean of its divisors is an integer number (5633292).

Almost surely, 2^20923643 is an apocalyptic number.

20923643 is a deficient number, since it is larger than the sum of its proper divisors (1609525).

20923643 is a wasteful number, since it uses less digits than its factorization.

20923643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1609524.

The product of its (nonzero) digits is 7776, while the sum is 29.

The square root of 20923643 is about 4574.2368762450. The cubic root of 20923643 is about 275.5576255469.

The spelling of 20923643 in words is "twenty million, nine hundred twenty-three thousand, six hundred forty-three".